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Heath
Kinds of Heath Terms modified by Heath Selected AbstractsEarly intervention with difficult to engage, ,high-risk' youth: evaluating an intensive outreach approach in youth mental healthEARLY INTERVENTION IN PSYCHIATRY, Issue 3 2008Carsten Schley Abstract Background: Although intensive outreach (IO) models such as assertive community treatment and intensive case management have a strong evidence base in adult psychiatry, their effectiveness in the early intervention sector is unknown. Aim: To explore client characteristics and treatment effects in a group of difficult to engage, ,high-risk' young people, seen by the Intensive Mobile Youth Outreach Service (IMYOS, ORYGEN Youth Heath) in Western Metropolitan Melbourne. Methods: The clinical files of 47 clients were audited, targeting demographic and treatment outcome data prior to and during IMYOS involvement. Results: Clients typically presented with traumatic childhoods, disrupted education, repeated treatment dropout, poor mental health and ,high-risk' behaviours. Results showed a significant reduction in risk to self and others between referral and discharge, and significantly lower admissions rates and inpatient days compared with the 9 months prior to referral. Conclusions: IO might be an effective early intervention strategy to minimize risk of harm and decrease hospitalization in young people. However, conclusions are provisional as there was no control group included in this study. Further study is required, perhaps with a waiting list control. [source] A score for Bayesian genome screeningGENETIC EPIDEMIOLOGY, Issue 3 2003E. Warwick Daw Abstract Bayesian Monte Carlo Markov chain (MCMC) techniques have shown promise in dissecting complex genetic traits. The methods introduced by Heath ([1997], Am. J. Hum. Genet. 61:748,760), and implemented in the program Loki, have been able to localize genes for complex traits in both real and simulated data sets. Loki estimates the posterior probability of quantitative trait loci (QTL) at locations on a chromosome in an iterative MCMC process. Unfortunately, interpretation of the results and assessment of their significance have been difficult. Here, we introduce a score, the log of the posterior placement probability ratio (LOP), for assessing oligogenic QTL detection and localization. The LOP is the log of the posterior probability of linkage to the real chromosome divided by the posterior probability of linkage to an unlinked pseudochromosome, with marker informativeness similar to the marker data on the real chromosome. Since the LOP cannot be calculated exactly, we estimate it in simultaneous MCMC on both real and pseudochromosomes. We investigate empirically the distributional properties of the LOP in the presence and absence of trait genes. The LOP is not subject to trait model misspecification in the way a lod score may be, and we show that the LOP can detect linkage for loci of small effect when the lod score cannot. We show how, in the absence of linkage, an empirical distribution of the LOP may be estimated by simulation and used to provide an assessment of linkage detection significance. Genet Epidemiol 24:181,190, 2003. © 2003 Wiley-Liss, Inc. [source] Social marketing in action,geodemographics, alcoholic liver disease and heavy episodic drinking in Great BritainINTERNATIONAL JOURNAL OF NONPROFIT & VOLUNTARY SECTOR MARKETING, Issue 3 2007Jane Powell This paper explores the use of geodemographic population classifications to identify and predict ,hotspots' of Great Britain (England, Scotland and Wales) prone to greater than expected alcoholic liver disease. MOSAIC geodemographic codes were overlaid onto Hospital Episode Statistics (HES) for Great Britain. The HES data included gender, MOSAIC Type, MOSAIC Code, postal and local authority district, month and year of birth, ethnic origin, Primary Care Trust and GP code. Analysis demonstrated that some geodemographic classifications of the population were over-represented for alcoholic liver disease episodes. These groups had low socio-economic and socio-cultural status, lived in areas of high deprivation and disadvantage. Manchester followed by Liverpool and Hull had the highest estimated patient group size in England and Hart, Surrey Heath and Wokingham the three lowest (indicating low expected levels of alcoholic liver disease compared with average). Analysis of the same data was also carried out at postcode level for Manchester indicating ,hotspots' for alcoholic level disease at street level. This analysis exemplifies the ways in which geodemographic data might be usefully applied to routine health service data to enhance service planning, delivery and improved targeting of information in harder to reach populations. Copyright © 2007 John Wiley & Sons, Ltd. [source] Dynamic Optimality of Yield Curve Strategies,INTERNATIONAL REVIEW OF FINANCE, Issue 1-2 2003Takao Kobayashi This paper formulates and analyzes a dynamic optimization problem of bond portfolios within Markovian Heath,Jarrow,Morton term structure models. In particular, we investigate optimal yield curve strategies analytically and numerically, and provide theoretical justification for a typical strategy which is recommended in practice for an expected change in the shape of the yield curve. In the numerical analysis, we utilize a new technique based on the asymptotic expansion approach in order to increase efficiency in computation. [source] Phonation type as a stylistic variable: The use of falsetto in constructing a persona1JOURNAL OF SOCIOLINGUISTICS, Issue 4 2007Robert J. Podesva Although the field of sociolinguistics has witnessed a growing interest in the sociophonetic aspects of segmental and intonational variation, few studies have examined variation in voice quality. This paper addresses the gap by investigating the stylistic use of falsetto phonation. Focusing on the speech of Heath, a speaker exhibiting considerable cross-situational variation, I show that when attending a barbecue with friends, Heath's falsetto is more frequent, longer, and characterized by higher fundamental frequency (f0) levels and wider f0 ranges. Advancing recent approaches to variation which treat linguistic features as stylistic resources for constructing social meaning, I draw on an analysis of the discourse contexts in which falsetto appears to illustrate that the feature carries expressive connotations. This meaning is employed to construct a ,diva' persona and may also participate in building a gay identity. [source] The distribution of heath balds in the Great Smoky Mountains, North Carolina and TennesseeJOURNAL OF VEGETATION SCIENCE, Issue 4 2001Peter S. White White (1982). Abstract. We used remote sensing and a geographic information system to model the distribution of evergreen shrub communities, called ,heath balds', in the Great Smoky Mountains, North Carolina and Tennessee, USA. The 421 heath balds averaged 1.8 ha in size and covered 0.3% of the landscape. They reached their greatest importance on upper slopes (92% had relative slope positions > 80), convex topography (82% occurred on sites with a curvature greater than 2.6), and elevations between 1100 and 1600 m (94% of the balds). Although heath balds were found in old-growth watersheds, the two watersheds with the greatest number of balds burned extensively after logging in the early 1900s. Bald occurrence was positively correlated with burned sites, old growth condition, and a highly acidic rock type. Heath balds showed a striking geographic pattern, with 88.1% of the area of this community found in six watersheds comprising only 35.4% of the study area. Despite similar topography, geology, and history, the eleven other watersheds had only 11.9% of the bald area while comprising 64.4% of the study area. Multivariate models showed that this community occurs on only 0.4 to 9.0% of the seemingly appropriate sites. Once established, this shrub community, with its dense evergreen canopy and thick leaf litter, is resistant to tree invasion. Both forest and shrub communities are stable on sites that are seemingly ideal for heath bald occurrence. [source] ANALYTICAL COMPARISONS OF OPTION PRICES IN STOCHASTIC VOLATILITY MODELSMATHEMATICAL FINANCE, Issue 1 2005Vicky Henderson This paper gives an ordering on option prices under various well-known martingale measures in an incomplete stochastic volatility model. Our central result is a comparison theorem that proves convex option prices are decreasing in the market price of volatility risk, the parameter governing the choice of pricing measure. The theorem is applied to order option prices under q -optimal pricing measures. In doing so, we correct orderings demonstrated numerically in Heath, Platen, and Schweizer (Mathematical Finance, 11(4), 2001) in the special case of the Heston model. [source] On the Existence of Finite-Dimensional Realizations for Nonlinear Forward Rate ModelsMATHEMATICAL FINANCE, Issue 2 2001Tomas Björk We consider interest rate models of the Heath,Jarrow,Morton type, where the forward rates are driven by a multidimensional Wiener process, and where the volatility is allowed to be an arbitrary smooth functional of the present forward rate curve. Using ideas from differential geometry as well as from systems and control theory, we investigate when the forward rate process can be realized by a finite-dimensional Markovian state space model, and we give general necessary and sufficient conditions, in terms of the volatility structure, for the existence of a finite-dimensional realization. A number of concrete applications are given, and all previously known realization results (as far as existence is concerned) for Wiener driven models are included and extended. As a special case we give a general and easily applicable necessary and sufficient condition for when the induced short rate is a Markov process. In particular we give a short proof of a result by Jeffrey showing that the only forward rate models with short rate dependent volatility structures which generically possess a short rate realization are the affine ones. These models are thus the only generic short rate models from a forward rate point of view. [source] Multiple Ratings Model of Defaultable Term StructureMATHEMATICAL FINANCE, Issue 2 2000Tomasz R. Bielecki A new approach to modeling credit risk, to valuation of defaultable debt and to pricing of credit derivatives is developed. Our approach, based on the Heath, Jarrow, and Morton (1992) methodology, uses the available information about the credit spreads combined with the available information about the recovery rates to model the intensities of credit migrations between various credit ratings classes. This results in a conditionally Markovian model of credit risk. We then combine our model of credit risk with a model of interest rate risk in order to derive an arbitrage-free model of defaultable bonds. As expected, the market price processes of interest rate risk and credit risk provide a natural connection between the actual and the martingale probabilities. [source] The Henry George Theorem and the Entrepreneurial Process: Turning Henry George on his HeadAMERICAN JOURNAL OF ECONOMICS AND SOCIOLOGY, Issue 1 2010Laurence S. Moss This chapter offers an interpretation of the Henry George Theorem (HGT) that brings it squarely into the study and analysis of entrepreneurship somewhat loosening its ties to the subfield of urban economics. I draw on the pioneering work of Spencer Heath whose insights about the viability of proprietary communities were developed further by his grandson, Spencer Heath MacCallum who, in 1970, recognized that private real estate developers sometimes make their capital gains (mostly) by creating useful public spaces that others enjoy. I also draw inspiration from Fred Foldvary's effort in 1994 to synthesize the pubic goods problem in economics with the Henry George Theorem in urban economics. While the real estate owner,developer does emerge on my pages in a somewhat more favourable light than as originally portrayed by Henry George in his Progress and Poverty in 1879, I offer a realistic appraisal of the duplicitous behaviours required of such entrepreneurs. in the context of the modern regulatory state. Real estate development remains a ,hot button' item in local politics, and real estate developers must become genuine ,political entrepreneurs' if they are to complete their projects in a timely way and capture business profits. It is a complicated story that the HGT helps make intelligible in terms of human action. [source] Variations of Somatotype in elderly SardiniansAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 4 2005R. Buffa Somatotyping is an effective technique for the study of anthropometric variations and body composition in elderly subjects, even though it has not often been used in this field. The present study was conducted on a sample of 280 healthy Sardinians (134 men and 146 women) of age 60,89 years, subdivided into three age classes (60,69 years; 70,79 years; and 80,89 years). Somatotypes were computed according to Carter and Heath (Somatotyping,Development and Applications. Cambridge, England: Cambridge University Press; 1990). The results show a dominance of the endo- and mesomorphic components in the elderly subjects, with less development of ectomorphy than in younger individuals. In a comparison with other populations, our sample shows strong development of endomorphy and especially of mesomorphy, while ectomorphy values are generally low. Age-related variations are significant in both sexes and consist in a progressive reduction of the endomorphic component, particularly in the 80,89-year class (endomorphy in the three age classes: 6.4, 6.1, and 5.3 in men; 8.1, 7.8, and 6.8 in women). The mesomorphic component is characterized by stability (age variations: 6.4, 6.4, and 5.9 in men; 6.3, 6.4, and 6.3 in women) and the ectomorphic component by a slight increase (age variations: 0.5, 0.6, and 0.8 in men; 0.4, 0.3, and 0.5 in women). Sex differences are significant and especially large for the endomorphic component, with generally higher values in women. The sexual dimorphism tends to decrease with age. The results are discussed with regard to the biology of aging, with emphasis on the potential application of somatotype to studies of the elderly population. Am. J. Hum. Biol. 17:403,411, 2005. © 2005 Wiley-Liss, Inc. [source] Pricing American options on foreign currency with stochastic volatility, jumps, and stochastic interest ratesTHE JOURNAL OF FUTURES MARKETS, Issue 9 2007Jia-Hau Guo By applying the Heath,Jarrow,Morton (HJM) framework, an analytical approximation for pricing American options on foreign currency under stochastic volatility and double jump is derived. This approximation is also applied to other existing models for the purpose of comparison. There is evidence that such types of jumps can have a critical impact on earlyexercise premiums that will be significant for deep out-of-the-money options with short maturities. Moreover, the importance of the term structure of interest rates to early-exercise premiums is demonstrated as is the sensitivity of these premiums to correlation-related parameters. © 2007 Wiley Periodicals, Inc. Jrl Fut Mark 27:867,891, 2007 [source] Multifactor and analytical valuation of treasury bond futures with an embedded quality optionTHE JOURNAL OF FUTURES MARKETS, Issue 3 2007Joăo Pedro Vidal Nunes A closed-form pricing solution is proposed for the quality option embedded in Treasury bond futures contracts, under a multifactor and D. Heath, R. Jarrow, and A. Morton (1992) Gaussian framework. Such an analytical solution can be obtained through a conditioning approximation, in the sense of M. Curran (1994) and L. Rogers and Z. Shi (1995), or via a rank 1 approximation, following A. Brace and M. Musiela (1994). Monte Carlo simulations show that both approximations are extremely accurate and easy to calculate. Application of the proposed pricing model to the EUREX market from January 2000 through May 2004, yields an excellent fit and an insignificant estimate of the quality option magnitude. On average, this delivery option accounts for only of the futures prices. © 2007 Wiley Periodicals, Inc. Jrl Fut Mark 27:275,303, 2007 [source] On Ethnography: Approaches to Language and Literacy Research , By Shirley Brice Heath and Brian V. Street, with Molly MillsANTHROPOLOGY & EDUCATION QUARTERLY, Issue 2 2009Aiko MiyatakeArticle first published online: 13 JUL 200 No abstract is available for this article. [source] Vegetation transition following drainage in a high-latitude hyper-oceanic ecosystemAPPLIED VEGETATION SCIENCE, Issue 2 2010Anna Maria Fosaa Abstract Questions: How does draining affect the composition of vegetation? Are certain functional groups favoured? Can soil parameters explain these differences? Location: Central Faroe Islands, treeless islands in the northern boreal vegetation zone. Since 1987, an area of 21 km2 at 100,200 m a.s.l. was drained in order to provide water for hydro-electric production. Method: Vegetation and soil of a drained area and a control, undrained neighbouring area of approximately the same size were sampled in 2007. Six sites were sampled in each area. The vegetation was classified with cluster analysis. Results: Four plant communities were defined in the area: Calluna vulgaris,Empetrum nigrum,Vaccinium myrtillus heath, Scirpus cespitosus,Eriophorum angustifolium blanket mire, Carex bigelowii,Racomitrium lanuginosum moss-heath, Narthecium ossifragum,Carex panacea mire. Heath was more extensively distributed within, and was the dominant community of the drained area, whereas moss-heath was more extensive in the undrained area. Blanket mire and mire had approximately the same distribution in both areas. For the blanket mire, species composition indicated drier conditions in the drained than in the undrained area. The drained area had higher frequencies of woody species and lichens, grasses had finer roots and available soil phosphate was considerably higher, whereas the undrained area had higher frequencies of grasses and sedges. Conclusion: The dominant plant communities were different in the two areas, which indicated that the blanket mire was drying in the drained area. Higher concentration of soil phosphate in the drained area also indicated increased decomposition of organic soils owing to desiccation. [source] A Comparison of the Soil Water, Nutrient Status, and Litterfall Characteristics of Tropical Heath and Mixed-Dipterocarp Forest Sites in Brunei,BIOTROPICA, Issue 1 2000Jonathan A. Moran ABSTRACT Two of the main hypotheses to explain the distribution and special characteristics of tropical heath forest are nutrient and water limitation. A study was undertaken to investigate both factors on two sites under tropical heath forest (Badas Forest Reserve) and mixed-dipterocarp forest (Andulau Forest Reserve) in Brunei. Soil water potentials were monitored at depths of 20, 50, and 90 cm over wet and dry periods for five months at each site. The results showed the mixed-dipterocarp forest site to be drier at 50 cm depth compared to the tropical heath forest site. There was no significant difference in water potentials between sites at 20 or 90 cm. Nutrient concentrations in the soil solution were monitored at the same depths over a seven-month period at the same sites. A 12-month litterfall study was also undertaken to monitor nutrient returns from the canopy at each site. The results of both studies suggest that the tropical heath forest site is poorer in nitrogen, but richer in calcium, than the mixed-dipterocarp forest site. The results for phosphorus are less clear, but do not suggest that its limitation is a significant factor at the tropical heath forest site compared to the mixed-dipterocarp forest site. Phosphorus and magnesium concentrations in the soil solution showed a strong positive correlation with sliding 30-day rainfall totals at both sites. [source] Soil production in heath and forest, Blue Mountains, Australia: influence of lithology and palaeoclimateEARTH SURFACE PROCESSES AND LANDFORMS, Issue 8 2005Marshall T. Wilkinson Abstract An Erratum has been published for this article in Earth Surfaces Processes and Landforms 25(13) 2005, 1683,1686. Recent determinations of soil production from in situ cosmogenic nuclides indicate that production decreases exponentially with soil depth. This contrasts with a long-held assumption that maximum soil production occurs under a soil cover of finite depth. Sites in the Blue Mountains, Australia, show a sharp decrease of soil depth where vegetation changes from forested plateau surfaces to heath-covered spurs, and bands of bare rock in the heath suggest that soil production depends on presence of a finite depth of soil. The substrate varies from hard ferruginized sandstone to soft saprolite. In situ 10Be determinations indicate that apparent rates of erosion and soil production are greater under the relatively thin heath soil than under the thicker forest soil but, in contrast to other studies, these sites do not show significant depth-dependence of apparent soil production. The pattern reflects both hardness variation in the rock substrate and the effect of Late Quaternary climatic change. Optically stimulated luminescence (OSL) dating indicates that soil ,30 cm depth is of Holocene age whereas the deeper soil is substantially older. The age-break coincides with a stone line interpreted as a former surface lag deposit. Assuming that pre-Holocene soil depths were 30 cm less than today, recalculated soil production tends to decrease with increasing depth. Soil production at this site requires soil cover but bare rock patches and vegetation comprise a shifting mosaic. In the long term, average rates of erosion and soil production decrease with increasing soil depth. Copyright © 2005 John Wiley & Sons, Ltd. [source] Weathering rates of buried machine-polished rock disks, Kärkevagge, Swedish LaplandEARTH SURFACE PROCESSES AND LANDFORMS, Issue 8 2002Colin E. Thorn Abstract Some 48 dolomite, 37 granite, and 19 limestone machine-polished disks were buried at soil horizon boundaries in 16 soil pits to maximum depths of 0·5,0·6 m within Kärkevagge, a presently periglacial, glaciated trough in Arctic Sweden. The objective of the ongoing study is to determine near-surface ,potential' weathering rates beneath birch forest, Dryas heath, heath, meadow, solifluction meadow, and willow vegetation cover types. Selected disks were excavated after 1 year, and all disks were excavated after 4 or 5 years. The limestone disks weathered fastest, followed closely by the dolomite disks, but the granite disks weathered at much slower rates. Mean annual percentage mass loss over 4 or 5 years was 0·473 ± 0·145% (two standard errors) for dolomite disks, 0·032 ± 0·005% (two standard errors) for granite disks, and 1·104 ± 0·446% (two standard errors) for limestone disks. For dolomite disks the Dryas heath and heath environments weathered the most slowly, a trend that was generally followed by the granite disks. Poor drainage (i.e. increasing wetness) and decreasing pH were found to promote dolomite weathering rates in a statistically significant manner. Surficial and subsurface weathering rates at individual sites were generally found to be correlated for dolomite, but not granite. Copyright © 2002 John Wiley & Sons, Ltd. [source] Impact of warming and timing of snow melt on soil microarthropod assemblages associated with Dryas- dominated plant communities on SvalbardECOGRAPHY, Issue 1 2006Rebecca Dollery Open Top Chambers (OTCs) were used to measure impacts of predicted global warming on the structure of the invertebrate community of a Dryas octopetala heath in West Spitsbergen. Results from the OTC experiment were compared with natural variation in invertebrate community structure along a snowmelt transect through similar vegetation up the adjacent hillside. Changes along this transect represent the natural response of the invertebrate community to progressively longer and potentially warmer and drier growing seasons. Using MANOVA, ANOVA, Linear Discriminant Analysis and ,2 tests, significant differences in community composition were found between OTCs and controls and among stations along the transect. Numbers of cryptostigmatic and predatory mites tended to be higher in the warmer OTC treatment but numbers of the aphid Acyrthosiphon svalbardicum, hymenopterous parasitoids, Symphyta larvae, and weevils were higher in control plots. Most Collembola, including Hypogastrura tullbergi, Lepidocyrtus lignorum and Isotoma anglicana, followed a similar trend to the aphid, but Folsomia bisetosa was more abundant in the OTC treatment. Trends along the transect showed clear parallels with the OTC experiment. However, mite species, particularly Diapterobates notatus, tended to increase in numbers under warming, with several species collectively increasing at the earlier exposed transect stations. Overall, the results suggest that the composition and structure of Arctic invertebrate communities associated with Dryas will change significantly under global warming. [source] Seedling dynamics of shrubs in a fully closed temperate forest: greater than expectedECOGRAPHY, Issue 5 2004N. A. Laskurain Shrub seedling emergences were studied in a beech-birch forest in the Basque Country (Spain). During four years (1998,2001) all emerging shrubs were tagged and regularly monitored in 198 1 m2 plots. Seedling emergence was intense during the entire study period and primarily occurred in early spring. Emerging seedlings mainly belonged to Hedera helix, Rubus gr. glandulosus and several heath species (including genera Erica, Calluna and Daboecia). In contrast, some dominant species components of the shrub layer (Vaccinium myrtillus and Lonicera periclymenum) showed no emergences. While small seeded species (heath species and Rubus) showed clear microsite preferences, avoiding litter for emergence, that was not the case of large seeded Hedera helix. Strict microsite requirements appear clearly associated with having seed bank, suggesting that this trait may allow these species to select favourable microenvironment prior to germination. Average life varied largely among the different taxa. It was very low for Rubus (7.4 months) and heath (4.9), and high for Hedera seedlings (23.1). Final survival was extremely low in the case of small-seeded species. Survival of Hedera seedlings was high, although their growth was very low, suggesting the existence of a conspicuous seedling bank. Our results clearly show that several shrubs species have dramatic seedling dynamics in full closed forest stands. Small seeded species preferentially emerge on bare surfaces in early spring from the soil seed banks. On the other hand, Hedera seedlings are able to emerge on litter and maintain a conspicuous seedling bank based on an efficient dispersal capability. [source] PCR profiling of ammonia-oxidizer communities in acidic soils subjected to nitrogen and sulphur depositionFEMS MICROBIOLOGY ECOLOGY, Issue 2 2007Christoph Stephan Schmidt Abstract Communities of ammonia-oxidizing bacteria (AOB) were characterized in two acidic soil sites experimentally subjected to varying levels of nitrogen and sulphur deposition. The sites were an acidic spruce forest soil in Deepsyke, Southern Scotland, with low background deposition, and a nitrogen-saturated upland grass heath in Pwllpeiran, North Wales. Betaproteobacterial ammonia-oxidizer 16S rRNA and ammonia monooxygenase (amoA) genes were analysed by cloning, sequencing and denaturing gradient gel electrophoresis (DGGE). DGGE profiles of amoA and 16S rRNA gene fragments from Deepsyke soil in 2002 indicated no effect of nitrogen deposition on AOB communities, which contained both Nitrosomonas europaea and Nitrosospira. In 2003, only Nitrosospira could be detected, and no amoA sequences could be retrieved. These results indicate a decrease in the relative abundance of AOB from the year 2002 to 2003 in Deepsyke soil, which may be the result of the exceptionally low rainfall in spring 2003. Nitrosospira -related sequences from Deepsyke soil grouped in all clusters, including cluster 1, which typically contains only sequences from marine environments. In Pwllpeiran soil, 16S rRNA gene libraries were dominated by nonammonia oxidizers and no amoA sequences were detectable. This indicates that autotrophic AOB play only a minor role in these soils even at high nitrogen deposition. [source] Fifteen years of climate change manipulations alter soil microbial communities in a subarctic heath ecosystemGLOBAL CHANGE BIOLOGY, Issue 1 2007RIIKKA RINNAN Abstract Soil microbial biomass in arctic heaths has been shown to be largely unaffected by treatments simulating climate change with temperature, nutrient and light manipulations. Here, we demonstrate that more than 10 years is needed for development of significant responses, and that changes in microbial biomass are accompanied with strong alterations in microbial community composition. In contrast to slight or nonsignificant responses after 5, 6 and 10 treatment years, 15 years of inorganic NPK fertilizer addition to a subarctic heath had strong effects on the microbial community and, as observed for the first time, warming and shading also led to significant responses, often in opposite direction to the fertilization responses. The effects were clearer in the top 5 cm soil than at the 5,10 cm depth. Fertilization increased microbial biomass C and more than doubled microbial biomass P compared to the non-fertilized plots. However, it only increased microbial biomass N at the 5,10 cm depth. Fertilization increased fungal biomass and the relative abundance of phospholipid fatty acid (PLFA) markers of gram-positive bacteria. Warming and shading decreased the relative abundance of fungal PLFAs, and shading also altered the composition of the bacterial community. The long time lag in responses may be associated with indirect effects of the gradual changes in the plant biomass and community composition. The contrasting responses to warming and fertilization treatments show that results from fertilizer addition may not be similar to the effects of increased nutrient mineralization and availability following climatic warming. [source] Variable sensitivity of plant communities in Iceland to experimental warmingGLOBAL CHANGE BIOLOGY, Issue 4 2005Ingibjörg S. Jónsdóttir Abstract Facing an increased threat of rapid climate change in cold-climate regions, it is important to understand the sensitivity of plant communities both in terms of degree and direction of community change. We studied responses to 3,5 years of moderate experimental warming by open-top chambers in two widespread but contrasting tundra communities in Iceland. In a species-poor and nutrient-deficient moss heath, dominated by Racomitrium lanuginosum, mean daily air temperatures at surface were 1,2°C higher in the warmed plots than the controls whereas soil temperatures tended to be lower in the warmed plots throughout the season. In a species-rich dwarf shrub heath on relatively rich soils at a cooler site, dominated by Betula nana and R. lanuginosum, temperature changes were in the same direction although more moderate. In the moss heath, there were no detectable community changes while significant changes were detected in the dwarf shrub heath: the abundance of deciduous and evergreen dwarf shrubs significantly increased (>50%), bryophytes decreased (18%) and canopy height increased (100%). Contrary to some other studies of tundra communities, we detected no changes in species richness or other diversity measures in either community and the abundance of lichens did not change. It is concluded that the sensitivity of Icelandic tundra communities to climate warming varies greatly depending on initial conditions in terms of species diversity, dominant species, soil and climatic conditions as well as land-use history. [source] Vegetation gradients in Atlantic Europe: the use of existing phytosociological data in preliminary investigations on the potential effects of climate change on British vegetationGLOBAL ECOLOGY, Issue 3 2000J. C. Duckworth Abstract 1This paper aims to demonstrate the use of available vegetation data from the phytosociological literature in preliminary analyses to generate hypotheses regarding vegetation and climate change. 2Data for over 3000 samples of calcareous grassland, mesotrophic grassland, heath and woodland vegetation were taken from the literature for a region in the west of Atlantic Europe and subjected to ordination by detrended correspondence analysis in order to identify the main gradients present. 3Climate data were obtained at a resolution of 0.5° from an existing database. The relationship between vegetation composition and climate was investigated by the correlation of the mean scores for the first two ordination axes for each 0.5° cell with the climate and location variables. 4The ordinations resulted in clear geographical gradients for calcareous grasslands, heaths and woodlands but not for mesotrophic grasslands. Significant correlations were shown between some of the vegetation gradients and the climate variables, with the strongest relationships occurring between the calcareous grassland gradients and July temperature, latitude and oceanicity. Some of the vegetation gradients were also inferred to reflect edaphic factors, management and vegetation history. 5Those gradients that were related to temperature were hypothesized to reflect the influence of a progressively warmer climate on species composition, providing a baseline for further studies on the influence of climate change on species composition. 6The validity of the literature data was assessed by the collection of an original set of field data for calcareous grasslands and the subsequent ordination of a dataset containing samples from both the literature and the field. The considerable overlap between the samples from the literature and the field suggest that literature data can be used, despite certain limitations. Such preliminary analyses, using readily available data, can thus achieve useful results, thereby saving lengthy and costly field visits. [source] Quantification of termite attack on lying dead wood by a line intersection method in the Kabili-Sepilok Forest Reserve, Sabah, MalaysiaINSECT CONSERVATION AND DIVERSITY, Issue 2 2008LENE BERGE Abstract., 1A line intersection method was used to estimate abundance (technically linear abundance: m1 m,2), biovolume (m3 ha,1) and size class distribution (defined by diameter) of lying dead wood in tropical forest. Additional semi-quantitative protocols assessed decay state (4 classes), termite attack (5 classes) and live termite occupancy (3 classes). 2Three forest types (kerangas, alluvial and sandstone) were sampled in the Kabili-Sepilok Forest Reserve of Eastern Sabah, using plots of 30 × 30 m. Approximately 50 man-hours were required per site, at a replication of three plots per site and three well-separated sites per forest type. 3Mean biovolume of lying dead wood exceeded 8 × 103 m3 ha,1 in kerangas (= heath) forest, with lower values in other types. Large items (> 19 cm diameter) were less than 10% of total abundance, but represented the largest biovolume, exceeding (alluvial) or equalling (kerangas) the total biovolumes of smaller categories combined. Most items (not less than 75%) were present as small wood (< 10 cm diameter). Items in the highest decay class had the highest biovolume. 4Termite attack was greater in the kerangas, where nearly 90% of items showed evidence of consumption, compared with 58% in the alluvial and 40% in the sandstone forests. Over 40% of items in the kerangas contained live termites compared with 25% in the alluvial and 15% in the sandstone. Items in the highest attack class (= almost total internal destruction) represented about one-half of the total biovolume available in the alluvial and kerangas forest types, and about one-third in the sandstone. [source] Validity of single-item parental ratings of child oral healthINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 6 2008DAVID LOCKER Objective. The aim of this study was to assess the validity of single-item parental ratings of child oral heath. Methods. Data were collected during a study to assess the impacts of dental injury. Clinical examinations of children aged 11,14 years were undertaken that included measures of trauma, decay, treatment needs, and fluorosis. Children with trauma and a group of trauma-free children were followed-up. Parents were mailed a questionnaire along with a questionnaire for the child that contained a short form of the Child Perceptions Questionnaire 11,14 (CPQ11,14). Bivariate analyses examined associations between parents' ratings of their child's oral health, measures of dental disease, clinically defined treatment needs, and scores on the CPQ11,14. Logistic regression was used to see if the associations observed remained after controlling for access to dental care variables. Results. Complete data were collected from 370 children and their parents. Parental ratings showed significant associations with most of the clinical indicators used and CPQ11,14 scores. Similar results were obtained when the data were analysed for subgroups defined by household income and mother's education. These associations remained after controlling for access to dental services. Conclusion. The data suggest that single-item parental ratings of child oral health have adequate construct validity. [source] Butterfly life history and temperature adaptations; dry open habitats select for increased fecundity and longevityJOURNAL OF ANIMAL ECOLOGY, Issue 1 2005BENGT KARLSSON Summary 1Evidence suggests that changes of temperature-related performance curves can trigger a selective response in life-history traits. Hence, it should be expected that insects adapted to different temperature regimes should exhibit optimal performance at the temperature to which they are adapted. 2To test this idea we investigated how fecundity and longevity are influenced by ambient temperatures in a set of satyrine butterflies adapted to live in dry open landscapes or in closed forest landscapes, respectively, by keeping egg-laying adult females at five different constant temperatures ranging between 20 and 40 °C. 3We studied four species, two of which are confined to dry and hot open habitats, namely the grayling (Hipparchia semele) and the small heath (Coenonympha pamphilus), and two of which are shade dwelling, namely the ringlet (Aphantopus hyperantus) and the speckled wood butterfly (Pararge aegeria). 4As predicted, the results showed that lifetime fecundity exhibited bell-shaped curves in relation to temperature with the open landscape group peaking at a higher temperature, 30 °C, compared with the shade-dwelling group that peaked at 25 °C. Longevity decreased with increasing temperatures among all species, but the open landscape living species survived better at higher temperatures. Moreover, although the magnitude of reproductive effort measured as lifetime egg mass did not differ between the two ecological groups, lifetime fecundity did with open landscape species laying more and smaller eggs than the shade-dwelling species. 5This difference in life-history character traits suggests either that dry and relatively warm open habitats open life-history opportunities in terms of higher fecundity and longevity that remain closed to butterflies adapted to cooler temperatures, or that life in dry open habitats actively selects for higher fecundity and survival as a result of increased offspring mortality. [source] Modern pollen,vegetation relationships in subarctic southern Greenland and the interpretation of fossil pollen data from the Norse landnámJOURNAL OF BIOGEOGRAPHY, Issue 3 2007J. Edward Schofield Abstract Aim, The objective of this paper is to explore the relationships that exist between vegetation and modern pollen rain in the open, largely treeless landscape of subarctic Greenland. The implications of these results for the interpretation of fossil pollen assemblages from the time of the Norse landnám are then examined. Location, The study area is the sheep farming district of Qassiarsuk in the subarctic, subcontinental vegetational and climatic zone of southern Greenland (61° N, 45° W). Between c.ad 1000,1500 this region was contained within the Norse Eastern Settlement. Methods, Detrended Correspondence Analysis (DCA) of harmonized plant,pollen data sets is used to compare plant cover in 64 vegetation quadrats with pollen assemblages obtained from moss polsters at matching locations. Presence/absence data are also used to calculate indices of association, over- and under-representation for pollen types. Results, Good correspondence between paired vegetation,pollen samples occurs in many cases, particularly in locations where Salix glauca,Betula glandulosa dwarf shrub heath is dominant, and across herbaceous field boundaries and meadows. Pollen samples are found to be poor at reflecting actual ground cover where ericales or Juniperus communis are the locally dominant shrubs. Dominant or ubiquitous taxa within this landscape (Betula, Salix and Poaceae) are found to be over-represented in pollen assemblages, as are several of the ,weeds' generally accepted as introduced by the Norse settlers. Main conclusions, Due to their over-representation in the pollen rain, many of the Norse apophytes and introductions (e.g. Rumex acetosa and R. acetosella) traditionally used to infer human activity in Greenland should be particularly sensitive indicators for landnám, allowing early detection of Norse activity in fossil assemblages. Pteridophyte spores are found to be disassociated with the ground cover of ferns and clubmosses, but are over-represented in pollen assemblages, indicating extra-local or regional sources and long residence times in soil/sediment profiles for these microfossils. A pollen record for Hordeum -type registered in close proximity to a field containing barley suggests that summer temperatures under the current climatic regime are, at least on occasion, sufficient to allow flowering. [source] Effects of global change on a sub-Arctic heath: effects of enhanced UV-B radiation and increased summer precipitationJOURNAL OF ECOLOGY, Issue 2 2001Gareth K. Phoenix Summary 1The responses of sub-Arctic heathland vegetation to enhanced UV-B radiation and increased summer precipitation over 7 years were investigated in a field experiment in northern Sweden. 2Growth, phenology and reproduction of the dominant dwarf shrubs Vaccinium myrtillus, V. uliginosum, V. vitis-idaea and Empetrum hermaphroditum were studied after 5,7 years of manipulation and retrospective analyses were used to assess growth responses in earlier years. Leaf tissue N and P and 13C natural abundances were determined for V. myrtillus and E. hermaphroditum. Growth responses were also assessed for the moss Hylocomium splendens. 3The deciduous V. myrtillus showed reduced growth, increased leaf thickness and increased flowering and berry production under enhanced UV-B in some years. V. uliginosum, V. vitis-idaea, E. hermaphroditum and H. splendens were, in general, tolerant of UV-B. 4Increased precipitation affected growth only in the evergreen species: stem length and branching were sometimes stimulated in E. hermaphroditum, whereas V. vitis-idaea showed reduced branching. 5Precipitation also increased leaf thickness in V. uliginosum and reduced flowering and berry production in V. myrtillus. 6In the interactions that occurred between enhanced UV-B radiation and increased summer precipitation, combining the two treatments often negated any effect that either may have had separately. The effect of concurrent increases on this ecosystem is therefore likely to be much less than if either occurred singly. 7Enhanced UV-B and increased summer precipitation appeared not to effect dwarf shrub abundances during the first 5 years of the experiment, suggesting that overall this heath may be more tolerant of these environmental changes than previously thought. [source] Type 2 diabetes and periodontal indicators: epidemiology in France 2002,2003JOURNAL OF PERIODONTAL RESEARCH, Issue 4 2006C. Mattout Background and Objective:, ,Diabetes and periodontal disease have been associated in the literature. In the present study, the periodontal heath of noninsulin-dependent diabetic adults was compared with that of a general population of nondiabetic patients. Material and Methods:, In France, 2144 adults (age: 35,65 years) were examined for life habits (tobacco, alcohol), biological diagnosis (type II diabetes, arterial hypertension), biometry (weight, size) and biochemistry. Dental and periodontal data included plaque index, gingival index, probing depth, and clinical attachment loss. Results:, Descriptive and multifactorial analysis evidenced a more severe periodontal disease in diabetic patients. Moreover, when the plaque index was held constant, the gingival index was more elevated in diabetics. In nondiabetics, age, gender, glycemia, alcohol, and tobacco smoking were identified as significant risk factors for periodontal disease. In contrast, in diabetic subjects, only tobacco smoking was a significant risk factor. Conclusion:, In type II diabetics, the diabetes factor is probably more significant than periodontal risk factors, age, and gender. [source] | |||||||||||||||||||||||||||||||||||||