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Burning
Kinds of Burning Terms modified by Burning Selected AbstractsIf Rome Is Burning, Why Are We Fiddling?CONSERVATION BIOLOGY, Issue 6 2006Brian Czech No abstract is available for this article. [source] Prescribed Burning to Restore Mixed-Oak Communities in Southern Ohio: Effects on Breeding- Bird PopulationsCONSERVATION BIOLOGY, Issue 5 2001Vanessa L. Artman We studied the effects of repeated burning (1,4 years of annual burning) and recovery (1 year after burning,) on the breeding bird community. Burning resulted in incremental but temporary reductions in the availability of leaf litter, shrubs, and saplings, but it did not affect trees, snags, or understory vegetation cover. Of 30 bird species monitored, 4 were affected negatively and 2 were affected positively by burning. Population densities of Ovenbirds ( Seiurus aurocapillus), Worm-eating Warblers ( Helmitheros vermivorus), and Hooded Warblers ( Wilsonia citrina) declined incrementally in response to repeated burning and did not recover within 1 year after burning, suggesting a lag time in response to the changes in habitat conditions. Densities of Northern Cardinals ( Cardinalis cardinalis) fluctuated among years in the control units, but remained low in the burned units. Densities of American Robins ( Turdus migratorius) and Eastern Wood-Pewees ( Contopus virens) increased in response to burning, but these increases were apparent only after several years of repeated burning. In general, burning resulted in short-term reductions in the suitability of habitat for ground- and low-shrub-nesting birds, but it improved habitat for ground- and aerial-foraging birds. Overall, there were no changes in the composition of the breeding-bird community. Total breeding bird population levels were also unaffected by burning. Our results suggest that prescribed burning applied on a long-term basis or across large spatial scales is likely to have adverse effects on ground- and low-shrub-nesting bird species, but other changes in the composition of the breeding-bird community are likely to be minimal as long as the closed-canopy forest structure is maintained within the context of prescribed burning. Resumen: Se está reintroduciendo fuego artificialmente en los bosque del sur de Ohio para determinar su efectividad para restaurar y mantener comunidades de bosques mixtos de encino ( Quercus spp.). Estudiamos los efectos de quemas repetidas (1,4 años de quema anual,) y de recuperación (1 año después de la quema) sobre la comunidad de aves reproductivas. La quema resultó en reducciones temporales en la disponibilidad de hojarasca, arbustos y renuevos, pero no afectó a los árboles, tocones o la cubierta vegetal del sotobosque. De 30 especies de aves monitoredas, 4 fueron afectadas negativamente por la quema y 2 fueron afectadas positivamente. Las densidades de población de Seiurus aurocapillus, de Helmitheros vermivorus y de Wilsonia citrina declinaron incrementalmente en respuesta a quemas repetidas y no se recuperaron en un año después de la quema, sugiriendo un retraso en el tiempo de respuesta a los cambios en las condiciones del hábitat. Las densidades de Cardinalis cardinalis fluctuaron entre años en las unidades control, pero permanecieron bajas en las unidades quemadas. Las densidades de Turdus migratorius y de Contopus virens aumentaron en respuesta a la quema, pero estos incrementos fueron evidentes sólo hasta varios años después de quemas repetidas. En general, en el corto plazo la quema resultó en reducciones en la calidad del hábitat para aves que anidan sobre el suelo y en arbustos bajos, pero mejoró el hábitat para aves que forrajean en el suelo y el aire. En general, no hubo cambios en la composición de la comunidad de aves reproductivas. Los niveles totales de poblaciones de aves reproductivas tampoco fueron afectados por la quema. Nuestros resultados sugieren la posibilidad de que la quema prescrita aplicada a largo plazo o en escalas espaciales grandes tenga efectos adversos sobre especies de aves que anidan sobre el suelo y en arbustos bajos, pero la posibilidad de cambios en la composición de la comunidad de aves reproductivas es mínima. [source] Burning and dripping behaviors of polymers under the UL94 vertical burning test conditionsFIRE AND MATERIALS, Issue 4 2010Yong Wang Abstract An experimental setup was constructed to record the real-time mass data of eight pure polymers under the UL94 vertical burning test conditions. The experiments showed that the flame rises up to the clamp or the dripping occurs soon for the pure polymers. The mass burned before the flame reaching the clamp and the dripping occurrence only accounts for a small fraction of the original mass of the specimen, which differentiates the UL94 test from the cone calorimeter test. The mass loss rate of polymer specimens is in the magnitude order of 0.001,0.01,g/s. It was also found that the flame of thin specimens usually reaches the clamp sooner than that of thick specimens. Apart from the dripping behaviors found in large-scale fires, it is found that the diameter of the first drop for the tested polymers is in the range of 2.0,10.0,mm. The mass of the first drop increases with the first dripping time. The first dripping time and the mass of the first drop increase with the thickness of the specimen, especially for polymers of large-size dripping type. Copyright © 2009 John Wiley & Sons, Ltd. [source] The importance of post-fire regrowth for sable antelope in a Southern African savannaAFRICAN JOURNAL OF ECOLOGY, Issue 2 2010Francesca Parrini Abstract Burning is commonly used in savannas to stimulate grass regrowth for grazing ungulates. We recorded the relative use of burns occurring at different stages in the seasonal cycle, as well as in different regions of the landscape by two herds of sable. We also recorded behavioural measures of foraging efficiency and faecal nutrient contents as an indication of nutrient gains. Sable consistently concentrated their grazing on burned areas provided there was sufficient green regrowth during the dry season. In these circumstances they grazed for longer per feeding station, showed a slower step rate while foraging, and shorter between-patch moves, and a higher probability of encountering acceptable food per step taken while foraging than on unburnt areas. In the year when only a burn with insufficient regrowth was available, sable continued to forage in the area that had been burned during the previous year. Faecal crude protein was substantially higher at the end of the dry season in the year when burned areas were utilized. Accordingly early dry season fires can be important in helping sable bridge the nutritional limitations posed by the dry season, provided sufficient soil moisture remains to promote adequate grass regrowth. Résumé Les feux sont fréquemment utilisés dans les savanes pour stimuler la repousse des herbes consommées par les ongulés herbivores. Nous avons enregistré l'utilisation relative des aires brûlées à différents stades du cycle saisonnier, et dans différentes régions du paysage, par deux hardes d'antilopes sable. Nous avons aussi enregistré des mesures comportementales de l'efficacité du nourrissage et le contenu en nutriments des matières fécales pour avoir une indication du gain en nutriments. Les antilopes sable concentraient leur pâturage de façon continue sur les aires brûlées pour autant que la repousse de verdure fût suffisante au cours de la saison sèche. Dans ce cas-là, elles paissaient plus longtemps par station de nourrissage, présentaient un nombre de pas plus faible en mangeant et se déplaçaient moins entre les arrêts, et la probabilité qu'elles rencontrent une nourriture acceptable par pas franchi en cherchant leur nourriture était plus grande que dans les zones non brûlées. L'année où ne fut disponible qu'une zone brûlée où la repousse était insuffisante, les antilopes ont continuéà brouter dans la zone qui avait été brûlée l'année précédente. Le taux de protéines brutes des matières fécales était substantiellement plus haut à la fin de la saison sèche l'année où les zones brûlées ont été utilisées. En fonction de cela, on peut dire que les feux du début de la saison sèche peuvent être importants pour aider les antilopes sable à passer le cap des limites nutritionnelles imposées par la saison sèche, à condition qu'il reste suffisamment d'humidité dans le sol pour favoriser une repousse d'herbes adéquate. [source] Burning and cutting: Identifying the traits of individuals with an enduring propensity to tan and to undergo cosmetic surgeryJOURNAL OF CONSUMER BEHAVIOUR, Issue 5 2009John C. Mowen The research investigated the trait predictors of the propensity to use two beautification procedures that have the potential to harm health , the propensities to tan and to obtain cosmetic surgery. The results of a survey of 231 adult consumers revealed that a different combination of hierarchically arranged traits was predictive of the two procedures. These results suggest that different strategies are required in order to market or demarket tanning and plastic surgery. The research also made methodological contributions by revealing that two forms of vanity identified in the literature , physical view vanity and physical concern vanity , represent two different constructs rather than two dimensions of an underlying construct. Copyright © 2009 John Wiley & Sons, Ltd. [source] Fresh insights into long-term changes in flora, vegetation, land use and soil erosion in the karstic environment of the Burren, western IrelandJOURNAL OF ECOLOGY, Issue 5 2009Ingo Feeser Summary 1. ,The study focuses on species-rich, upland, heathy vegetation with arctic-alpine floristic affinities and Sesleria grasslands in the karstic Burren region, western Ireland. The investigations aimed at reconstructing the long-term development of these high conservation-value communities and the role of farming in their formation and long-term survival. 2. ,The methods used included pollen analysis and 14C-dating of short monoliths and investigation of grykes (fissures in karstic limestone) for evidence of soil erosion. Special attention was paid to fossil, coprophilous fungal spores as indicators of local grazing. The strong local character of the pollen records facilitated identification of inter-site differences as well as regional patterns. It is shown that open pine woodland characterized the Cappanawalla uplands between c. 1500 BC and 500 BC. It is proposed that such woodlands, with floristic affinities to Scandinavian open pine woodlands on calcareous soils, provided a suitable environment for the present-day, open heath vegetation with species such as Dryas octopetala, Arctostaphylos uva-ursi, Geranium sanguineum and Empetrum nigrum. 3. ,Burning of vegetation as a management tool was important in the uplands over most of the last two millennia. Firing seems to have ceased with the onset of more intensive grazing regimes in the 18th century. 4. ,Synthesis. Upland palaeoarchives, derived from shallow peaty deposits, show that the upland Burren supported mainly plagioclimax Corylus -dominated woody vegetation and grasslands from c. 1500 BC (beginning of present record), until possibly as late as the 17th century AD. In the uplands of the north-western Burren, open, species-rich pinewoods with hazel dominated. The northern-arctic elements in the present-day upland flora survived clearances, involving initially Pinus sylvestris (c. 500 BC) and subsequently Corylus avellana (c. AD 1600). Colluvial material retrieved from grykes supports the idea of considerable soil loss occurring as late as the first and early 2nd millennium AD. The investigations highlight the potential of upland palaeoarchives, consisting of short sequences, for elucidating vegetation and land-use dynamics in karstic environments such as the Burren. [source] Increasing the Effectiveness of Reed canary grass (Phalaris arundinacea L.) Control in Wet Meadow RestorationsRESTORATION ECOLOGY, Issue 3 2006Carrie Reinhardt Adams Abstract Restoration practices are often based on trial and error or anecdotal information because data from controlled experiments are not available. In wet meadow restorations of the upper Midwest United States, Reed canary grass (Phalaris arundinacea L.) is controlled with spring burning and spring glyphosate herbicide applications, but the relative effectiveness of either treatment with respect to P. arundinacea growth and life history has not been assessed. We designed a multiyear field experiment to evaluate effects of burning and herbicide application timings on P. arundinacea populations. Burning did not reduce P. arundinacea biomass but reduced the P. arundinacea seed bank, potentially limiting recolonization of P. arundinacea. Glyphosate applications in late August and late September were more effective than in mid-May (due to enhanced glyphosate translocation to rhizomes), such that two mid-May applications reduced P. arundinacea biomass to a level equivalent to that achieved by one late-season application. Phalaris. arundinacea recolonized rapidly from the seed bank and, in plots that received suboptimally timed (mid-May) herbicide, from rhizomes. Establishment of native species was very low, likely due to competition with recolonizing P. arundinacea. Unplanted species (from the seed bank and refugial populations) accounted for the majority of non- P. arundinacea biomass. Recolonization of other species was strongly limited by a threshold level of P. arundinacea biomass. Adequate site preparation (over multiple growing seasons) and aftercare (selective removal of P. arundinacea) will be the key to facilitating subsequent wet meadow vegetation establishment. This research provides an example of the importance of experimental evidence as the basis to improve the efficiency of restoration practices. [source] Prescribed fire and conservation of a threatened mountain grassland specialist: a capture,recapture study on the Orsini's viper in the French alpsANIMAL CONSERVATION, Issue 3 2009A. Lyet Abstract Burning has traditionally been used in the southern French Alps to maintain open lands for grazing. In the context of land use abandonment, prescribed burning may be the only realistic practical tool available to oppose encroachment by woody plants in numerous mountainous landscapes. Although only recently developed as a modern tool for wildfire prevention and management of pastoral grasslands, this practice is now becoming widespread, which raises the issue of its impact on the fauna in general, and on endangered species in particular. We studied the impact of a prescribed fire on the survival and small-scale movements of one of the rarest snakes in Europe, the Orsini's viper Vipera ursinii, in order to evaluate its potential threat to population sustainability. We evaluated the body condition of snakes and the quality of their habitat, more precisely the abundance of grasshoppers as the main food resource, and the vegetation cover as shelter. About 3.6 ha of a 8.8 ha study site was burnt in autumn 2003. Snake population parameters were estimated using multi-state capture,mark,recapture methods. We demonstrate that burning reduced the survival of the vipers by more than half during the first year following the fire. Contrary to what was expected, there was no evidence of emigration from the burned to the unburned area immediately after the fire. Despite the decrease in grasshopper density and vegetation cover in the burned area, there was no evidence of mid-term mortality in snakes that could result from an increased predation rate or from the reduced body condition of snakes. As such high mortality, mainly or entirely due to the direct effect of fire, is likely to have large repercussions on population sustainability, we suggest several improvements of prescribed fire protocols to minimize their impact and strongly emphasize the need for a prescribed fire policy that takes into account specific recommendations for threatened species like Orsini's viper. The case of the Orsini's viper is very typical of conservation problems in open mountain lands, and we believe that our research will help determine the most suitable approach for long-term conservation of biodiversity in such semi-natural ecosystems. [source] Three centuries of fire in montane pine-oak stands on a temperate forest landscapeAPPLIED VEGETATION SCIENCE, Issue 1 2010Serena R. Aldrich Abstract Question: What was the role of fire in montane pine-oak (Pinus-Quercus) stands under changing human land uses on a temperate forest landscape in eastern North America? Location: Mill Mountain in the central Appalachian Mountains, Virginia, US. Methods: A dendroecological reconstruction of fire history was generated for four stands dominated by xerophytic pine and oak species. The fire chronology began under presettlement conditions following aboriginal depopulation. Subsequent land uses included European settlement, iron mining, logging, and US Forest Service acquisition and fire protection. Results: Fires occurred approximately every 5 years until 1930 without any evidence of a temporal trend in fire frequency. Burning ceased after 1930. Area-wide fires affecting multiple pine stands were common, occurring at intervals of approximately 16 years. Most living pines became established during the late 1800s and early 1900s. Dead pines indicated that an older cohort established ca. 1730. Most hardwoods were established between the 1920s and 1940s. Conclusions: Except for fire protection, changes in land use had no discernible influence on fire frequency. Lightning ignitions and/or large fire extent may have been important for maintaining frequent burning in the 1700s, while fuel recovery may have constrained fire frequency during later periods. The disturbance regime appears to be characterized by frequent surface fires and occasional severe fires, insect outbreaks or other disturbances followed by pine recruitment episodes. Industrial disturbances appear to have had little influence on the pine stands. The greatest impact of industrial society is fire exclusion, which permitted hardwood establishment. [source] Experiments on the mechanism of tree and shrub establishment in temperate grassy woodlands: Seedling emergenceAUSTRAL ECOLOGY, Issue 4 2001Peter J. Clarke Abstract Field experiments were designed to examine tree and shrub seedling emergence in temperate grassy woodlands on the New England Tablelands. The effects of study sites, intensity of previous grazing, removal of ground cover by fire or clearing, burial of seeds and ant seed theft on seedling emergence were tested in two field experiments. Six tree and seven shrub species were used in the experiments and their cumulative emergence was compared with laboratory germination studies. All species used in field experiments had lower cumulative emergence than those in laboratory germination studies despite prolonged periods of above average rainfall before and after seeds were sown. Eucalypt species emerged faster in the field than the shrub species and generally attained higher cumulative emergence than the shrubs. Spatial effects of sites and patches within sites, and of previous grazing history did not strongly influence patterns of seedling emergence in most species. Ground and litter cover generally did not enhance or suppress the emergence of seedlings, although the removal of cover in recently grazed areas enhanced the emergence of some species. Burning enhanced the emergence of some tree and shrub species where plots had more fuel and intense fires, but this effect was not strong. Compared with other treatments, seedbed manipulations produced the strongest effects. In the absence of both invertebrate and vertebrate predators, seedling emergence was lower for surface-sown seed, compared with seed sown on scarified soil surfaces. Higher seedling emergence of buried seeds in the presence of invertebrate predators probably resulted from the combined effects of predator escape and enhanced moisture status of the germination environment. Some promotion of emergence was achieved for all species in most sown treatments probably as a result of a prolonged above average rainfall. In contrast, the natural recruitment of trees and shrubs was negligible in experimental plots, highlighting the importance of seed supply and dispersal as ultimate determinants of recruitment. [source] ,The Day of Burning': Eviction and Reinvention in the Margins of Northwest ZimbabweJOURNAL OF AGRARIAN CHANGE, Issue 4 2001Amanda Hammar A violent eviction in a remote northwestern corner of Zimbabwe in late 1997 provides a prism through which to explore the changing dynamics of competition over space, power and production in Zimbabwe's agrarian margins, where con?ict over wildlife and agriculture has intensi?ed and the state has become a key player. The article argues that in its quest to (re)gain control over one such location, the state has had to construct it as space of violence in order to de-civilize it and reinvent it as a wilderness zone. The ,day of burning' is taken not only as a signi?er of the violent potential of such competition, but also as a metaphor for the state's increasing loss of legitimacy in the margins: that is, the ,burning away' of any residue of illusion about the state as either the democratic embodiment of the people's will or compassionate provider of services and security. [source] Allergic Conjunctivitis and Contact Lenses: Experience with Olopatadine Hydrochloride 0.1% TherapyACTA OPHTHALMOLOGICA, Issue 2000M. Brodsky ABSTRACT. Objective: The efficacy of Patanol®, a topically applied anti-allergic agent, was evaluated in a group of patients with allergic conjunctivitis due to contact lens wear (GROUP I) and a group comprised of seasonal allergic conjunctivitis patients, vernal conjunctivitis patients and atopic keratoconjunctivitis patients (GROUP II). Methods: One drop of Patanol® was administered to each eye twice daily. Signs and symptoms were assessed 7, 14, and 28 days after initiation of drug therapy. Results: Itching/burning, tearing, hyperemia and papillary reaction were reduced to scores of 0/1 (absent/mild) in 85%, 90%, 81% and 62%, respectively, of GROUP I patients at Day 28. The allergic conditions in GROUP II patients also improved with Patanol® treatment. Itching/burning, tearing, hyperemia and papillary reactions were absent/mild in 60%, 76%, 96% and 90%, respectively, of these patients at Day 28. Conclusion: Patanol® treatment effectively and rapidly alleviated the signs and symptoms of allergic conjunctivitis due to contact lens wear as well as vernal conjunctivitis, atopic keratoconjunctivitis and the common seasonal allergic conjunctivitis. Patanol® allowed allergic patients to be more comfortable while permitting them to continue using contact lenses. [source] Improving realism of a surgery simulator: linear anisotropic elasticity, complex interactions and force extrapolationCOMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3 2002Guillaume Picinbono Abstract In this article, we describe the latest developments of the minimally invasive hepatic surgery simulator prototype developed at INRIA. The goal of this simulator is to provide a realistic training test bed to perform laparoscopic procedures. Therefore, its main functionality is to simulate the action of virtual laparoscopic surgical instruments for deforming and cutting tridimensional anatomical models. Throughout this paper, we present the general features of this simulator including the implementation of several biomechanical models and the integration of two force-feedback devices in the simulation platform. More precisely, we describe three new important developments that improve the overall realism of our simulator. First, we have developed biomechanical models, based on linear elasticity and finite element theory, that include the notion of anisotropic deformation. Indeed, we have generalized the linear elastic behaviour of anatomical models to ,transversally isotropic' materials, i.e. materials having a different behaviour in a given direction. We have also added to the volumetric model an external elastic membrane representing the ,liver capsule', a rather stiff skin surrounding the liver, which creates a kind of ,surface anisotropy'. Second, we have developed new contact models between surgical instruments and soft tissue models. For instance, after detecting a contact with an instrument, we define specific boundary constraints on deformable models to represent various forms of interactions with a surgical tool, such as sliding, gripping, cutting or burning. In addition, we compute the reaction forces that should be felt by the user manipulating the force-feedback devices. The last improvement is related to the problem of haptic rendering. Currently, we are able to achieve a simulation frequency of 25,Hz (visual real time) with anatomical models of complex geometry and behaviour. But to achieve a good haptic feedback requires a frequency update of applied forces typically above 300,Hz (haptic real time). Thus, we propose a force extrapolation algorithm in order to reach haptic real time. Copyright © 2002 John Wiley & Sons, Ltd. [source] Bayesian Networks and Adaptive Management of Wildlife HabitatCONSERVATION BIOLOGY, Issue 4 2010ALISON L. HOWES herramientas para la toma de decisiones; incertidumbre ecológica; pastoreo feral; regímenes de quema; validación de modelos Abstract:,Adaptive management is an iterative process of gathering new knowledge regarding a system's behavior and monitoring the ecological consequences of management actions to improve management decisions. Although the concept originated in the 1970s, it is rarely actively incorporated into ecological restoration. Bayesian networks (BNs) are emerging as efficient ecological decision-support tools well suited to adaptive management, but examples of their application in this capacity are few. We developed a BN within an adaptive-management framework that focuses on managing the effects of feral grazing and prescribed burning regimes on avian diversity within woodlands of subtropical eastern Australia. We constructed the BN with baseline data to predict bird abundance as a function of habitat structure, grazing pressure, and prescribed burning. Results of sensitivity analyses suggested that grazing pressure increased the abundance of aggressive honeyeaters, which in turn had a strong negative effect on small passerines. Management interventions to reduce pressure of feral grazing and prescribed burning were then conducted, after which we collected a second set of field data to test the response of small passerines to these measures. We used these data, which incorporated ecological changes that may have resulted from the management interventions, to validate and update the BN. The network predictions of small passerine abundance under the new habitat and management conditions were very accurate. The updated BN concluded the first iteration of adaptive management and will be used in planning the next round of management interventions. The unique belief-updating feature of BNs provides land managers with the flexibility to predict outcomes and evaluate the effectiveness of management interventions. Resumen:,El manejo adaptativo es un proceso interactivo de recopilación de conocimiento nuevo relacionado con el comportamiento de un sistema y el monitoreo de las consecuencias ecológicas de las acciones de manejo para refinar las opciones de manejo. Aunque el concepto se originó en la década de los 1970s, rara vez es incorporado activamente en la restauración ecológica. Las redes Bayesianas (RBs) están emergiendo como herramientas eficientes para la toma de decisiones ecológicas en el contexto del manejo adaptativo, pero los ejemplos de su aplicación en este sentido son escasos. Desarrollamos una RB en el marco del manejo adaptativo que se centra en el manejo de los efectos del pastoreo feral y los regímenes de quemas prescritas sobre la diversidad de aves en bosques subtropicales del este de Australia. Construimos la RB con datos para predecir la abundancia de aves como una función de la estructura del hábitat, la presión de pastoreo y las quemas prescritas. Los resultados del análisis de sensibilidad sugieren que la presión de pastoreo incrementó la abundancia de melífagos agresivos, que a su vez tuvieron un fuerte efecto negativo sobre paserinos pequeños. Posteriormente se llevaron a cabo intervenciones de manejo para reducir la presión del pastoreo feral y quemas prescritas, después de las cuales recolectamos un segundo conjunto de datos de campo para probar la respuesta de paserinos pequeños a estas medidas. Utilizamos estos datos, que incorporaron cambios ecológicos que pueden haber resultado de la intervención de manejo, para validar y actualizar la RB. Las predicciones de la abundancia de paserinos pequeños bajo las nuevas condiciones de hábitat y manejo fueron muy precisas. La RB actualizada concluyó la primera iteración de manejo adaptativo y será utilizada para la planificación de la siguiente ronda de intervenciones de manejo. La característica única de actualización de la RBs permite que los manejadores tengan flexibilidad para predecir los resultados y evaluar la efectividad de las intervenciones de manejo. [source] Patch-Occupancy Modeling as a Method for Monitoring Changes in Forest Floristics: a Case Study in Southeastern AustraliaCONSERVATION BIOLOGY, Issue 3 2009TRENT D. PENMAN fuego prescrito; manejo adaptativo; modelo Bayesiamo; silvicultura; tala Abstract:,The ability to monitor changes in biodiversity is fundamental to demonstrating sustainable management practices of natural resources. Disturbance studies generally focus on responses at the plot scale, whereas landscape-scale responses are directly relevant to the development of sustainable forest management. Modeling changes in occupancy is one way to monitor landscape-scale responses. We used understory vegetation data collected over 16 years from a long-term study site in southeastern Australia. The site was subject to timber harvesting and frequent prescribed burning. We used occupancy models to examine the impacts of these disturbances on the distribution of 50 species of plants during the study. Timber harvesting influenced the distribution of 9 species, but these effects of harvesting were generally lost within 14 years. Repeated prescribed fire affected 22 species, but the heterogeneity of the burns reduced the predicted negative effects. Twenty-two species decreased over time independent of treatment, and only 5 species increased over time. These changes probably represent a natural response to a wildfire that occurred in 1973, 13 years before the study began. Occupancy modeling is a useful and flexible technique for analyzing monitoring data and it may also be suitable for inclusion within an adaptive-management framework for forest management. Resumen:,La habilidad para monitorear cambios en la biodiversidad es fundamental para demostrar el manejo sustentable de los recursos naturales. Los estudios de perturbación generalmente enfocan las respuestas a escala de parcela, mientras que las respuestas a escala de paisaje son directamente relevantes para el desarrollo del manejo sustentable de bosques. El modelado de cambios en la ocupación es una forma de monitorear respuestas a escala de paisaje. Utilizamos datos de la vegetación de sotobosque colectados a los largo de 16 años en un sitio de estudio a largo plazo en el sureste de Australia. El sitio fue sujeto a la cosecha de madera y a quemas prescritas frecuentes. Utilizamos modelos de ocupación para examinar los impactos de estas perturbaciones sobre la distribución de 50 especies de plantas. La cosecha de madera influyó en la distribución de nueve especies, pero los efectos de la cosecha generalmente se perdieron al cabo de 14 años. El fuego prescrito repetido afectó a 22 especies, pero la heterogeneidad de las quemas redujo los efectos negativos pronosticados. Veintidós especies decrecieron en el tiempo independientemente del tratamiento, y solo cinco especies incrementaron en el tiempo. Estos cambios probablemente representan una respuesta natural al incendio no controlado que ocurrió en 1973, 13 años antes de que comenzara el estudio. El modelado de la ocupación es una técnica útil y flexible para analizar datos de monitoreo y también puede ser adecuado para su inclusión en un marco de manejo adaptativo para la gestión de bosques. [source] Modeled Effects of Sagebrush-Steppe Restoration on Greater Sage-Grouse in the Interior Columbia Basin, U.S.A.CONSERVATION BIOLOGY, Issue 5 2002Michael J. Wisdom Consequently, managers of FS,BLM lands need effective strategies to recover sagebrush (Artemisia spp.) habitats on which this species depends. In response to this need, we evaluated the potential benefits of two restoration scenarios on Greater Sage-Grouse in the interior Columbia Basin and adjacent portions of the Great Basin of the western United States. Scenario 1 assumed a 50% reduction in detrimental grazing effects (through changes in stocking rates and grazing systems) and a six-fold increase in areas treated with active restoration (e.g., prescribed burning, native seedings, wildfire suppression) compared with future management proposed by the FS,BLM. Scenario 2 assumed a 100% reduction in detrimental grazing effects and the same increase in active restoration as scenario 1. To evaluate benefits, we estimated the risk of population extirpation for sage grouse 100 years in the future under the two scenarios and compared this risk with that estimated for proposed (100-year) FS,BLM management. We used estimates of extirpation risk for historical (circa 1850,1890) and current time periods as a context for our comparison. Under historical conditions, risk of extirpation was very low on FS,BLM lands, but increased to a moderate probability under current conditions. Under proposed FS,BLM management, risk of extirpation on FS,BLM lands increased to a high probability 100 years in the future. Benefits of the two restoration scenarios, however, constrained the future risk of extirpation to a moderate probability. Our results suggest that expansive and sustained habitat restoration can maintain desired conditions and reduce future extirpation risk for sage grouse on FS,BLM lands in western North America. The continued spread of exotic plants, however, presents a formidable challenge to successful restoration and warrants substantial research and management attention. Resumen: Los hábitats del urogallo (Centrocercus urophasianus) han disminuido a lo largo de la región occidental de Norteamérica, y la mayoría de los hábitats restantes ocurren en terrenos administrados por el Servicio Forestal de E.U.A. (SF) y el Buró de Administración de Tierras ( BAT ). Por lo tanto, los encargados de las tierras SF,BAT necesitan estrategias eficaces para recuperar los hábitats de artemisa (Artemisia spp.) de los cuales depende esta especie. En respuesta a esta necesidad, evaluamos los beneficios potenciales de dos escenarios de restauración sobre el urogallo en el interior de la Cuenca del Columbia y porciones adyacentes de la Gran Cuenca del occidente de los Estados Unidos. El escenario 1 supone una reducción del 50% en los efectos perjudiciales del pastoreo ( por medio de cambios en las tasas de aprovisionamiento y en los sistemas de pastoreo) y un incremento de seis veces en la superficie de las áreas tratadas con restauración activa ( por ejemplo, quemas prescritas, plántulas nativas, supresión de fuego no controlado) comparada con la administración futura propuesta por el SF,BAT. El escenario 2 supone una reducción del 100% en los efectos de pastoreo perjudiciales y el mismo aumento en la restauración activa que en el escenario 1. Para evaluar los beneficios, estimamos el riesgo de extirpación de la población de urogallos en 100 años bajo los dos escenarios y comparamos este riesgo con el riesgo estimado por la propuesta de manejo de SF,BAT (100-años). Utilizamos estimaciones del riesgo de extirpación en períodos históricos (entre 1850 y 1890) y actuales como contexto para nuestra comparación. Bajo condiciones históricas, el riesgo de extirpación fue muy bajo en los terrenos SF,BAT pero aumentó a una probabilidad moderada bajo condiciones actuales. Bajo la administración propuesta por SF,BAT, el riesgo de extirpación en los terrenos SF,BAT aumentó a una alta probabilidad 100 años en el futuro. Sin embargo, los beneficios de los dos escenarios de restauración constriñen el riesgo de extirpación a una probabilidad moderada. Nuestros resultados sugieren que la restauración expansiva y sostenida del hábitat puede mantener condiciones deseadas y reduce el riesgo de extirpación de urogallos en terrenos SF,BAT en la región occidental de Norteamérica. Sin embargo, la continua extensión de plantas exóticas representa un reto formidable para la restauración exitosa y justifica considerable investigación y atención de manejo. [source] Prescribed Burning to Restore Mixed-Oak Communities in Southern Ohio: Effects on Breeding- Bird PopulationsCONSERVATION BIOLOGY, Issue 5 2001Vanessa L. Artman We studied the effects of repeated burning (1,4 years of annual burning) and recovery (1 year after burning,) on the breeding bird community. Burning resulted in incremental but temporary reductions in the availability of leaf litter, shrubs, and saplings, but it did not affect trees, snags, or understory vegetation cover. Of 30 bird species monitored, 4 were affected negatively and 2 were affected positively by burning. Population densities of Ovenbirds ( Seiurus aurocapillus), Worm-eating Warblers ( Helmitheros vermivorus), and Hooded Warblers ( Wilsonia citrina) declined incrementally in response to repeated burning and did not recover within 1 year after burning, suggesting a lag time in response to the changes in habitat conditions. Densities of Northern Cardinals ( Cardinalis cardinalis) fluctuated among years in the control units, but remained low in the burned units. Densities of American Robins ( Turdus migratorius) and Eastern Wood-Pewees ( Contopus virens) increased in response to burning, but these increases were apparent only after several years of repeated burning. In general, burning resulted in short-term reductions in the suitability of habitat for ground- and low-shrub-nesting birds, but it improved habitat for ground- and aerial-foraging birds. Overall, there were no changes in the composition of the breeding-bird community. Total breeding bird population levels were also unaffected by burning. Our results suggest that prescribed burning applied on a long-term basis or across large spatial scales is likely to have adverse effects on ground- and low-shrub-nesting bird species, but other changes in the composition of the breeding-bird community are likely to be minimal as long as the closed-canopy forest structure is maintained within the context of prescribed burning. Resumen: Se está reintroduciendo fuego artificialmente en los bosque del sur de Ohio para determinar su efectividad para restaurar y mantener comunidades de bosques mixtos de encino ( Quercus spp.). Estudiamos los efectos de quemas repetidas (1,4 años de quema anual,) y de recuperación (1 año después de la quema) sobre la comunidad de aves reproductivas. La quema resultó en reducciones temporales en la disponibilidad de hojarasca, arbustos y renuevos, pero no afectó a los árboles, tocones o la cubierta vegetal del sotobosque. De 30 especies de aves monitoredas, 4 fueron afectadas negativamente por la quema y 2 fueron afectadas positivamente. Las densidades de población de Seiurus aurocapillus, de Helmitheros vermivorus y de Wilsonia citrina declinaron incrementalmente en respuesta a quemas repetidas y no se recuperaron en un año después de la quema, sugiriendo un retraso en el tiempo de respuesta a los cambios en las condiciones del hábitat. Las densidades de Cardinalis cardinalis fluctuaron entre años en las unidades control, pero permanecieron bajas en las unidades quemadas. Las densidades de Turdus migratorius y de Contopus virens aumentaron en respuesta a la quema, pero estos incrementos fueron evidentes sólo hasta varios años después de quemas repetidas. En general, en el corto plazo la quema resultó en reducciones en la calidad del hábitat para aves que anidan sobre el suelo y en arbustos bajos, pero mejoró el hábitat para aves que forrajean en el suelo y el aire. En general, no hubo cambios en la composición de la comunidad de aves reproductivas. Los niveles totales de poblaciones de aves reproductivas tampoco fueron afectados por la quema. Nuestros resultados sugieren la posibilidad de que la quema prescrita aplicada a largo plazo o en escalas espaciales grandes tenga efectos adversos sobre especies de aves que anidan sobre el suelo y en arbustos bajos, pero la posibilidad de cambios en la composición de la comunidad de aves reproductivas es mínima. [source] Possible Environmental Factors Underlying Amphibian Decline in Eastern Puerto Rico: Analysis of U.S. Government Data ArchivesCONSERVATION BIOLOGY, Issue 4 2001Robert F. Stallard I examined changes in environmental conditions by examining time-series data sets that extend back at least into the 1980s, a period when frog populations were declining. The data include forest cover; annual mean, minimum, and maximum daily temperature; annual rainfall; rain and stream chemistry; and atmospheric-dust transport. I examined satellite imagery and air-chemistry samples from a single National Aeronautics and Space Administration aircraft flight across the Caribbean showing patches of pollutants, described as thin sheets or lenses, in the lower troposphere. The main source of these pollutants appeared to be fires from land clearing and deforestation, primarily in Africa. Some pollutant concentrations were high and, in the case of ozone, approached health limits set for urban air. Urban pollution impinging on Puerto Rico, dust generation from Africa ( potential soil pathogens), and tropical forest burning ( gaseous pollutants) have all increased during the last three decades, overlapping the timing of amphibian declines in eastern Puerto Rico. None of the data sets pointed directly to changes so extreme that they might be considered a direct lethal cause of amphibian declines in Puerto Rico. More experimental research is required to link any of these environmental factors to this problem. Resumen: Las pasadas tres décadas han visto grandes disminuciones poblacionales de especies de anfibios en altas elevaciones de Puerto Rico oriental, una región única en los trópicos húmedos debido al grado de monitoreo ambiental que se ha llevado a cabo mediante los esfuerzos de las agencias de gobierno de los Estados Unidos. Examiné los cambios en condiciones ambientales mediante el análisis de datos de series de tiempo que se extienden hasta los 1980s, un periodo en el que las poblaciones de ranas estaban declinando. Los datos incluyen cobertura forestal; temperatura diaria media, mínima y máxima anual; precipitación anual; química de la lluvia y arroyos; y el transporte atmosférico de polvo. Examiné imágenes de satélite y muestras de química del aire obtenidos de un solo vuelo de una nave de la NASA a lo largo del Caribe que mostraba parches de contaminantes descritas como capas delgadas de lentes en la inferior troposfera. La mayor fuente de contaminantes parece ser los incendios de tierras clareadas y la deforestación, principalmente en África. Algunas concentraciones de contaminantes fueron altas y en el caso del ozono, se aproximó a los límites de salud establecidos para aire urbano. La contaminación urbana afectando a Puerto Rico, la generación de polvo en África ( patógenos del suelo potenciales) y la quema de bosque tropical (contaminantes gaseosos) han incrementado durante las últimas tres décadas, superponiéndose con el periodo en que oturrieron las disminuciones de anfibios en Puerto Rico oriental. Ninguno de estos conjuntos de datos señaló directamente hacia cambios tan extremos que debieran ser considerados como una causa letal directa de las disminuciones en Puerto Rico. Se requiere de más investigación experimental que vincule a estos factores ambientales con este problema. [source] Management of vulvar painDERMATOLOGIC THERAPY, Issue 1 2004Gayle Fischer ABSTRACT:, Vulvodynia is a frequently used medical term that literally means "vulvar pain". Therefore, vulvodynia is a symptom, not a disease. The term itself indicates a variety of unpleasant chronic vulvar sensations, including burning, rawness, soreness, irritation, sensitivity, and formication. This may or may not include dyspareunia. Primary vulvodynia occurs when these sensory disturbances occur in the absence of observable dermatologic disease or vulvovaginal infection. There are several causes for this, including neuropathy, referred pain, and pelvic floor muscle dysfunction. For the purist, it is the patient in whom there is no observable reason for vulvar pain who represents the true case of vulvodynia. However, vulvodynia can also occur secondarily as a symptom of vulvar skin disease. Restricting the present paper to patients without objective signs leaves out all the important conditions which come into the differential diagnosis of vulvar pain which should be ruled out first. The first step in managing vulvodynia is making an accurate diagnosis of its cause. The present review summarizes the diagnosis and management of the chronic dermatologic diseases which may cause primary and secondary vulvodynia. The etiology of primary vulvodynia is much more poorly understood than secondary vulvodynia, and treatment of some aspects remains controversial. [source] The role of environmental gradients in non-native plant invasion into burnt areas of Yosemite National Park, CaliforniaDIVERSITY AND DISTRIBUTIONS, Issue 2 2006Rob Klinger ABSTRACT Fire is known to facilitate the invasion of many non-native plant species, but how invasion into burnt areas varies along environmental gradients is not well-understood. We used two pre-existing data sets to analyse patterns of invasion by non-native plant species into burnt areas along gradients of topography, soil and vegetation structure in Yosemite National Park, California, USA. A total of 46 non-native species (all herbaceous) were recorded in the two data sets. They occurred in all seven of the major plant formations in the park, but were least common in subalpine and upper montane conifer forests. There was no significant difference in species richness or cover of non-natives between burnt and unburnt areas for either data set, and environmental gradients had a stronger effect on patterns of non-native species distribution, abundance and species composition than burning. Cover and species richness of non-natives had significant positive correlations with slope (steepness) and herbaceous cover, while species richness had significant negative correlations with elevation, the number of years post-burn, and cover of woody vegetation. Non-native species comprised a relatively minor component of the vegetation in both burnt and unburnt areas in Yosemite (percentage species = 4%, mean cover < 6.0%), and those species that did occur in burnt areas tended not to persist over time. The results indicate that in many western montane ecosystems, fire alone will not necessarily result in increased rates of invasion into burnt areas. However, it would be premature to conclude that non-native species could not affect post-fire succession patterns in these systems. Short fire-return intervals and high fire severity coupled with increased propagule pressure from areas used heavily by humans could still lead to high rates of invasion, establishment and spread even in highly protected areas such as Yosemite. [source] Prescribed-fire effects on rill and interrill runoff and erosion in a mountainous sagebrush landscape ,EARTH SURFACE PROCESSES AND LANDFORMS, Issue 2 2009Frederick B. Pierson Abstract Changing fire regimes and prescribed-fire use in invasive species management on rangelands require improved understanding of fire effects on runoff and erosion from steeply sloping sagebrush-steppe. Small (0·5 m2) and large (32·5 m2) plot rainfall simulations (85 mm h,1, 1 h) and concentrated flow methodologies were employed immediately following burning and 1 and 2 years post-fire to investigate infiltration, runoff and erosion from interrill (rainsplash, sheetwash) and rill (concentrated flow) processes on unburned and burned areas of a steeply sloped sagebrush site on coarse-textured soils. Soil water repellency and vegetation were assessed to infer relationships in soil and vegetation factors that influence runoff and erosion. Runoff and erosion from rainfall simulations and concentrated flow experiments increased immediately following burning. Runoff returned to near pre-burn levels and sediment yield was greatly reduced with ground cover recovery to 40 per cent 1 year post-fire. Erosion remained above pre-burn levels on large rainfall simulation and concentrated flow plots until ground cover reached 60 per cent two growing seasons post-fire. The greatest impact of the fire was the threefold reduction of ground cover. Removal of vegetation and ground cover and the influence of pre-existing strong soil-water repellency increased the spatial continuity of overland flow, reduced runoff and sediment filtering effects of vegetation and ground cover, and facilitated increased velocity and transport capacity of overland flow. Small plot rainfall simulations suggest ground cover recovery to 40 per cent probably protected the site from low-return-interval storms, large plot rainfall and concentrated flow experiments indicate the site remained susceptible to elevated erosion rates during high-intensity or long duration events until ground cover levels reached 60 per cent. The data demonstrate that the persistence of fire effects on steeply-sloped, sandy sagebrush sites depends on the time period required for ground cover to recover to near 60 per cent and on the strength and persistence of ,background' or fire-induced soil water repellency. Published in 2009 by John Wiley & Sons, Ltd. [source] The effects of green tree retention and subsequent prescribed burning on ground beetles (Coleoptera: Carabidae) in boreal pine-dominated forestsECOGRAPHY, Issue 5 2006Petri Martikainen We studied how two methods to promote biodiversity in managed forests, i.e. green tree retention and prescribed fire, affect the assemblages of carabid beetles. Our experiment consisted of 24 study sites, each 3,5 ha in size, which had been prepared according to factorial design. Each of the eight treatment combinations determined by the two factors explored , tree retention level (0, 10, 50 m3/ha,1 and uncut controls) and prescribed use of fire (yes/no) , was replicated three times. We sampled carabids using pitfall traps one year after the treatments. Significantly more individuals were caught in most of the burned sites, but this difference was partially reflective of the trap-catches of Pterostichus adstrictus. The fire did not increase no. of P. adstrictus in the uncut sites as much as in the other sites. Species richness was significantly affected by both factors, being higher in the burned than in the unburned sites and in the harvested than in the unharvested sites. Many species were concentrated in the groups of retention trees in the burned sites, but only a few were in the unburned sites. The species turnover was greater in the burned than in the unburned sites, as indicated by the NMDS ordinations. Greater numbers of smaller sized species and proportion of brachypterous species were present in the burned sites. Fire-favored species, and also the majority of other species that prefer open habitats were more abundantly caught in the burned sites than in the unburned sites. Dead wood or logging waste around the traps did not correlate with the occurrence of species. We conclude that carabids are well adapted to disturbances, and that frequent use of prescribed fire is essential for the maintenance of natural assemblages of carabid beetles in the boreal forest. Small retention tree groups can not maintain assemblages of uncut forest, but they can be important by providing food, shelter and breeding sites for many species, particularly in the burned sites. [source] The Role of Information in Repeated Games With Frequent ActionsECONOMETRICA, Issue 3 2010Yuliy Sannikov We show that in repeated interactions the avenues for effective provision of incentives depend crucially on the type of information players observe. We establish this conclusion for general repeated two-player games in which information arrives via a continuous-time stationary process that has a continuous multidimensional Brownian component and a Poisson component, and in which the players act frequently. The Poisson jumps can be used to effectively provide incentives both with transfers and value burning, while continuous Brownian information can be used to provide incentives only with transfers. [source] A preliminary characterization of the mutagenicity of atmospheric particulate matter collected during sugar cane harvesting using the Salmonella/microsome microsuspension assayENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 4 2008Gisela de Aragão Umbuzeiro Abstract During sugar cane harvesting season, which occurs from May to November of each year, the crops are burnt, cut, and transported to the mills. There are reports showing that mutagenic activity and PAH content increase during harvesting season in some areas of São Paulo State in comparison with nonharvesting periods. The objective of this work was to preliminarily characterize the mutagenic activity of the total organic extracts as well as corresponding organic fractions of airborne particulate matter (PM) collected twice from two cities, Araraquara (ARQ) and Piracicaba (PRB), during sugar cane harvesting season using the Salmonella/microsome microssuspension assay. One sample collected in São Paulo metropolitan area was also included. The mutagenicity of the total extracts ranged from 55 to 320 revertants per cubic meter without the addition of S9 and from not detected to 57 revertants per cubic meter in the presence of S9 in areas with sugar cane plantations. Of the three fractions analyzed, the most polar ones (nitro and oxy) were the most potent. A comparison of the response of TA98 with YG1041 and the increased potencies without S9 indicated that nitro compounds are causing the observed effect. More studies are necessary to verify the sources of the mutagenic activity such as burning of vegetal biomass and combustion of heavy duty vehicles used to transport the sugar cane to the mills. The Salmonella/microsome assay can be an important tool to monitor the atmosphere for mutagenicity during sugar cane harvesting season. Environ. Mol. Mutagen. 2008. © 2008 Wiley-Liss, Inc. [source] DNA damage in mice treated with sulfur dioxide by inhalationENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 3 2005Ziqiang Meng Abstract Sulfur dioxide (SO2) is a ubiquitous air pollutant produced by the burning of fossil fuels. In this study, single-cell gel electrophoresis (the Comet assay) was used to evaluate the DNA damage produced by inhalation exposure of mice to SO2. Male and female mice were housed in exposure chambers and treated with 14.00 ± 1.25, 28.00 ± 1.98, 56.00 ± 3.11, and 112.00 ± 3.69 mg/m3 SO2 for 6 hr/day for 7 days, while control groups were exposed to filtered air. Comet assays were performed on blood lymphocytes and cells from the brain, lung, liver, spleen, kidney, intestine, and testicles of the animals. SO2 caused significant, dose-dependent increases in DNA damage, as measured by Olive tail moment, in all the cell types analyzed from both sexes of mice. The results indicate that inhalation exposure to SO2 damages the DNA of multiple organs in addition to the lung, and suggests that this damage could result in mutation, cancer, and other diseases related to DNA damage. Further work will be required to understand the ultimate toxicological significance of this damage. These data also suggest that detecting DNA damage in blood lymphocytes, using the Comet assay, may serve as a useful tool for evaluating the impact of pulmonary SO2 exposure in human biomonitoring studies. Environ. Mol. Mutagen., 2005. © 2005 Wiley-Liss, Inc. [source] Apportionment of polycyclic aromatic hydrocarbon sources in lower Fox River, USA, sediments by a chemical mass balance modelENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2000Ming-Chien Su Abstract Four sediment cores were collected from the lower Fox River, Wisconsin, USA, to identify possible sources of polycyclic aromatic hydrocarbons (PAHs) using a chemical mass balance model. The cores, which were obtained in 1995 from areas close to Green Bay, Wisconsin, USA, had total PAH concentrations between 19.3 and 0.34 ppm. To determine historical trends of PAH inputs, 210Pb and 137Cs dating was used, and elemental carbon particle analysis was done to characterize particles from the combustion of coal, wood, and petroleum. Source fingerprints were taken from the literature. Our results indicate that coke oven emissions, highway dust, coal gasification, and wood burning are likely sources of PAHs in the lower Fox River. Coke oven emissions are in the range of 40 to 90% of total PAHs, and this fraction decreases from 1930 to 1990, except in core Fox River,A (FR-A). The overall highway dust (HWY) contribution is between 10 and 75%, and this fraction increases from 1930 to present, except in core FR-A. The wood burning (WB) contribution (i.e., wood burning or coal gasification) is less than 7% in cores FR-B, FR-C, and FR-D. In core FR-A, a maximum (,23%) is found around 1960. The contribution of wood burning has changed from less than 6% in 1950 to between 3 and 10% in 1995. Evidence of aerobic biodegradation or photolysis in the sediment of phenanthrene, with a half-life of approximately 0.5 years has been found at the site of core FR-D, which is the shallowest (1.1 m) of the four core sites. [source] Probabilistic risk modeling at the wildland urban interface: the 2003 Cedar FireENVIRONMETRICS, Issue 6 2009D. R. Brillinger Abstract The October 2003 Cedar Fire in San Diego County was a tragedy involving 15 deaths, the burning of some 280,000,acres of land, the destruction of approximately 2227 homes, and costs of suppression near $30 million. It was the largest fire in California history. The data associated with the fire, however, do provide an opportunity to carry out probabilistic risk modeling of a wildland-urban interface (WUI) event. WUI's exist where humans and their development interface with wildland fuel. As home building expands from urban areas to nearby forest areas, these homes become more likely to burn. Wildfires are an exceedingly complex phenomenon with uncertainty and unpredictability abounding, hence a statistical approach to gaining insight appears useful. In this research, spatial stochastic models are developed. These relate risk probabilities and losses measures to a variety of available explanatory quantities. There is a consideration of economic aspects and a discussion of the difficulties that arose in developing the data and of carrying out the analyses. Purposes of the work include highlighting a statistical method, developing variates associated with a destruction probability and employing the fitted risk probability to estimate future and possible losses. Copyright © 2008 John Wiley & Sons, Ltd. [source] Occupational exposure to methyl tertiary butyl ether in relation to key health symptom prevalence: the effect of measurement error correctionENVIRONMETRICS, Issue 6 2003Aparna P. Keshaviah Abstract In 1995, White et al. reported that methyl tertiary butyl ether (MTBE), an oxygenate added to gasoline, was significantly associated with key health symptoms, including headaches, eye irritation, and burning of the nose and throat, among 44 people occupationally exposed to the compound and for whom serum MTBE measurements were available (odds ratio (OR),=,8.9, 95% CI,=,[1.2, 75.6]). However, these serum MTBE measurements were available for only 29 per cent of the 150 subjects enrolled. Around the same time, Mannino et al. conducted a similar study among individuals occupationally exposed to low levels of MTBE and did not find a significant association between exposure to MTBE and the presence of one or more key health symptoms among the 264 study participants (OR,=,0.60, 95% CI,=,[0.3, 1.21]). In this article, we evaluate the effect of MTBE on the prevalence of key health symptoms by applying a regression calibration method to White et al.'s and Mannino et al.'s data. Unlike White et al., who classified exposure using actual MTBE levels among a subset of the participants, and Mannino et al., who classified exposure based on job category among all participants, we use all of the available data to obtain an estimate of the effect of MTBE in units of serum concentration, adjusted for measurement error due to using job category instead of measured exposure. After adjusting for age, gender and smoking status, MTBE exposure was found to be significantly associated with a 50 per cent increase in the prevalence of one or more key health symptoms per order of magnitude increase in blood concentration on the log10 scale, using data from the 409 study participants with complete information on the covariates (95% CI,=,[1.00, 2.25]). Simulation results indicated that under conditions similar to those observed in these data, the estimator is unbiased and has a coverage probability close to the nominal value. The methodology illustrated in this article is advantageous because all of the available data were used in the analysis, obtaining a more precise estimate of exposure effect on health outcome, and the estimate is adjusted for measurement error due to using job category instead of measured exposure. Copyright © 2003 John Wiley & Sons, Ltd. [source] Analysis of rain quality data from the South African interiorENVIRONMETRICS, Issue 4 2002Jacky Galpin Abstract Rain acidity may be ascribed to emissions from power station stacks, as well as emissions from other industry, biomass burning, maritime influences, agricultural influences, etc. Rain quality data are available for 30 sites in the South African interior, some from as early as 1985 for up to 14 rainfall seasons, while others only have relatively short records. The article examines trends over time in the raw and volume weighted concentrations of the parameters measured, separately for each of the sites for which sufficient data are available. The main thrust, however, is to examine the inter-relationship structure between the concentrations within each rain event (unweighted data), separately for each site, and to examine whether these inter-relationships have changed over time. The rain events at individual sites can be characterized by approximately eight combinations of rainfall parameters (or rain composition signatures), and these are common to all sites. Some sites will have more events from one signature than another, but there appear to be no signatures unique to a single site. Analysis via factor and cluster analysis, with a correspondence analysis of the results, also aid interpretation of the patterns. This spatio-temporal analysis, performed by pooling all rain event data, irrespective of site or time period, results in nine combinations of rainfall parameters being sufficient to characterize the rain events. The sites and rainfall seasons show patterns in these combinations of parameters, with some combinations appearing more frequently during certain rainfall seasons. In particular, the presence of the combination of low acetate and formate with high magnesium appears to be increasing in the later rainfall seasons, as does this combination together with calcium, sodium, chloride, potassium and fluoride. As expected, sites close together exhibit similar signatures. Copyright © 2002 John Wiley & Sons, Ltd. [source] Micromorphological evidence of black carbon in colluvial soils from NW SpainEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 6 2008J. Kaal Summary Biomass burning produces a residue called black carbon (BC). Black C is generally considered to be highly resistant against biodegradation and has a potential role in the global C cycle, but is difficult to identify and quantify when subjected to prolonged degradation in terrestrial sediments. The colluvial soils from Campo Lameiro (NW Spain), also known as ,Atlantic rankers', are rich in organic matter (up to 140 g C kg,1 soil). A micromorphological study was undertaken to test the hypothesis that a large proportion of the organic matter was derived from BC formed during Holocene wildfires (up to > 6000 years ago). As roughly estimated from image analysis of 12 thin sections, the volumetric BC contribution ranged between 10 and 60% (26% on average) of the organic matter. This is a conservative estimate as additional morphologically unrecognizable BC was present in the microgranular matrix of coalesced excrement. We conclude that (i) currently unknown quantities of BC are stored in Atlantic rankers and (ii) analysis of thin sections is an effective tool to identify BC. [source] | |||||||||||||||||||||||||||||||||||||||||||