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Cumulative Effects (cumulative + effects)
Selected AbstractsFROM CRISIS TO CUMULATIVE EFFECTS: FOOD SECURITY CHALLENGES IN ALASKAANNALS OF ANTHROPOLOGICAL PRACTICE, Issue 1 2009David V. Fazzino Recent increases in the price of fuel in rural Alaska, coupled with high prices of grocery store foods and decreased efficacy of hunting and fishing have led to a food crisis in many regions of rural Alaska. In the summer of 2008 it was predicted that these events would lead to an upswing in the number of individuals migrating to urban areas of Alaska, putting additional stress on the already dwindling resources of food assistance providers. Through discussions with food assistance providers in Fairbanks, Alaska, a research program was designed to assess how well recent migrants were able to meet their food needs. In total 39 individuals were interviewed in November and December 2008, using face-to-face, semistructured interviews. This article discusses a smaller subset of the overall interviews, namely the responses of Natives who currently live in Fairbanks, Alaska. Further, this article informs understandings of "crisis" in the global sense, highlighting the importance of placing "crises" into the larger context of cumulative effects which are long-term and differentially distributed, rather than treating them as discrete and individually mitigatable events. [source] Grammar Acquisition and Processing Instruction: Secondary and Cumulative Effects,by BENATI, ALESSANDRO G., & JAMES F. LEEMODERN LANGUAGE JOURNAL, Issue 1 2010CLAUDIA FERNÁNDEZ No abstract is available for this article. [source] Cumulative effects of in utero administration of mixtures of reproductive toxicants that disrupt common target tissues via diverse mechanisms of toxicityINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 2 2010C. V. Rider Summary Although risk assessments are typically conducted on a chemical-by-chemical basis, the 1996 Food Quality Protection Act required the US Environmental Protection Agency to consider cumulative risk of chemicals that act via a common mechanism of toxicity. To this end, we are conducting studies with mixtures of chemicals to elucidate mechanisms of joint action at the systemic level with the goal of providing a framework for assessing the cumulative effects of reproductive toxicants. Previous mixture studies conducted with antiandrogenic chemicals are reviewed briefly and two new studies are described. In all binary mixture studies, rats were dosed during pregnancy with chemicals, singly or in pairs, at dosage levels equivalent to approximately one-half of the ED50 for hypospadias or epididymal agenesis. The binary mixtures included androgen receptor (AR) antagonists (vinclozolin plus procymidone), phthalate esters [di(n-butyl) phthalate (DBP) plus benzyl n-butyl phthalate (BBP) and diethyl hexyl phthalate (DEHP) plus DBP], a phthalate ester plus an AR antagonist (DBP plus procymidone), a mixed mechanism androgen signalling disruptor (linuron) plus BBP, and two chemicals which disrupt epididymal differentiation through entirely different toxicity pathways: DBP (AR pathway) plus 2,3,7,8 TCDD (AhR pathway). We also conducted multi-component mixture studies combining several ,antiandrogens'. In the first study, seven chemicals (four pesticides and three phthalates) that elicit antiandrogenic effects at two different sites in the androgen signalling pathway (i.e. AR antagonist or inhibition of androgen synthesis) were combined. In the second study, three additional phthalates were added to make a 10 chemical mixture. In both the binary mixture studies and the multi-component mixture studies, chemicals that targeted male reproductive tract development displayed cumulative effects that exceeded predictions based on a response-addition model and most often were in accordance with predictions based on dose-addition models. In summary, our results indicate that compounds that act by disparate mechanisms of toxicity to disrupt the dynamic interactions among the interconnected signalling pathways in differentiating tissues produce cumulative dose-additive effects, regardless of the mechanism or mode of action of the individual mixture component. [source] Transforming tropical rivers: an environmental perspective on hydropower development in Costa RicaAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 7 2006Elizabeth P. Anderson Abstract 1.Tropical rivers are increasingly being altered by hydropower dams. In Costa Rica, more than 30 hydropower plants were built during the 1990s and more dams are being proposed. Hydropower dams currently provide more than 80% of electricity consumed by the country's 4 million residents, yet most of Costa Rica's hydropower potential remains untapped. 2.Ecological consequences of dams in Costa Rica stem primarily from river fragmentation, stream de-watering, and downstream hydrological alterations. Dams affect distribution and abundance of aquatic biota, especially migratory species. Cumulative effects of multiple dams on individual river basins, especially in the northern part of the country, are also of concern but have not been adequately documented. 3.In light of recent hydropower development, we recommend conservation strategies that protect remaining free-flowing rivers, call for assessment of ecological impacts of dams on a broader scale, encourage research on aquatic systems and sustainable hydropower technologies, and promote the development of methods for estimating environmental flows for Costa Rican rivers. Copyright © 2006 John Wiley & Sons, Ltd. [source] Salvage Logging, Ecosystem Processes, and Biodiversity ConservationCONSERVATION BIOLOGY, Issue 4 2006D.B. LINDENMAYER conservación de la biodiversidad; gestión forestal; procesos ecosistémicos Abstract:,We summarize the documented and potential impacts of salvage logging,a form of logging that removes trees and other biological material from sites after natural disturbance. Such operations may reduce or eliminate biological legacies, modify rare postdisturbance habitats, influence populations, alter community composition, impair natural vegetation recovery, facilitate the colonization of invasive species, alter soil properties and nutrient levels, increase erosion, modify hydrological regimes and aquatic ecosystems, and alter patterns of landscape heterogeneity. These impacts can be assigned to three broad and interrelated effects: (1) altered stand structural complexity; (2) altered ecosystem processes and functions; and (3) altered populations of species and community composition. Some impacts may be different from or additional to the effects of traditional logging that is not preceded by a large natural disturbance because the conditions before, during, and after salvage logging may differ from those that characterize traditional timber harvesting. The potential impacts of salvage logging often have been overlooked, partly because the processes of ecosystem recovery after natural disturbance are still poorly understood and partly because potential cumulative effects of natural and human disturbance have not been well documented. Ecologically informed policies regarding salvage logging are needed prior to major natural disturbances so that when they occur ad hoc and crisis-mode decision making can be avoided. These policies should lead to salvage-exemption zones and limits on the amounts of disturbance-derived biological legacies (e.g., burned trees, logs) that are removed where salvage logging takes place. Finally, we believe new terminology is needed. The word salvage implies that something is being saved or recovered, whereas from an ecological perspective this is rarely the case. Resumen:,Resumimos los impactos documentados y potenciales de la cosecha de salvamento , una forma de cosecha de madera que remueve árboles y otros materiales biológicos después de una perturbación natural. Tales operaciones pueden reducir o eliminar legados biológicos, modificar hábitats post perturbación, influir en poblaciones, alterar la composición de comunidades, impedir la recuperación de la vegetación natural, facilitar la colonización de especies invasoras, alterar las propiedades del suelo y de niveles de nutrientes, incrementar la erosión, modificar regímenes hidrológicos y ecosistemas acuáticos, y alterar patrones de heterogeneidad del paisaje. Estos impactos se pueden asignar a tres efectos amplios e interrelacionados: (1) alteración de la complejidad estructural del bosque; (2) alteración de procesos y funciones ecológicas; y (3) alteración de poblaciones de especies y de la composición de la comunidad. Algunos impactos pueden ser diferentes a o adicionales a los efectos de la cosecha de madera tradicional que no es precedida de una perturbación natural severa porque las condiciones antes, durante y después de la cosecha de salvamento pueden diferir de las que caracterizan a la cosecha de madera tradicional. Los impactos potenciales de la cosecha de salvamento a menudo han sido pasados por alto, en parte porque los procesos de recuperación del ecosistema después de una perturbación natural son poco conocidos y en parte porque los efectos acumulativos potenciales de perturbaciones naturales y humanas no han sido bien documentados. Se requieren políticas ecológicamente informadas para la cosecha de salvamento para que cuando ocurran las perturbaciones naturales se evite la toma de decisiones en situaciones de crisis. Estas políticas deberán establecer zonas exentas de salvamento y límites a las cantidades de legados biológicos derivados de la perturbación (e. g., árboles quemados, troncos) que son removidos donde se lleva a cabo la cosecha de salvamento. Finalmente, creemos que se requiere una nueva terminología. La palabra salvamento implica que algo esta siendo salvado o recuperado, y este raramente es el caso desde una perspectiva ecológica. [source] From Policy to Practice: Challenges in Infant Feeding in Emergencies During the Balkan CrisisDISASTERS, Issue 2 2001Annalies Borrel The preparation and dissemination of policy statements are necessary but insufficient to prevent the inappropriate use of infant-feeding products in emergencies. The widespread failure of humanitarian agencies operating in the Balkan crisis to act in accordance with international policies and recommendations provides a recent example of the failure to translate infant-feeding policies into practice. This article explores the underlying reasons behind the failures which include: (1) the weak institutionalisation of policies; (2) the massive quantities of unsolicited donations of infant-feeding products; (3) the absence of monitoring systems; (4) inadequate co-ordination mechanisms; (5) the high costs of correcting mistakes; and (6) the cumulative effects of poor practice. Efforts to uphold best practice during the crisis are also documented. Finally, the article identifies actions that could be undertaken in advance of and during future emergencies to enhance the application of infant feeding policies in emergencies. [source] Visual, auditory and cross-modal processing of linguistic and nonlinguistic temporal patterns among adult dyslexic readersDYSLEXIA, Issue 2 2005Ann Meyler Abstract This study examined visual, auditory, and cross-modal temporal pattern processing at the nonlinguistic and sublexical linguistic levels, and the relationships between these abilities and decoding skill. The central question addressed whether dyslexic readers are impaired in their perception of timing, as assessed by sensitivity to rhythm. Participants were college-level adult dyslexic and normal readers. The dyslexic adults evidenced generalized impairment in temporal processing: they were less accurate and slower than normal readers when required to detect the temporal gap that differentiated pairs of patterns. Impairment was greatest when processing visual syllables. Temporal pattern processing correlated to decoding ability only among normal readers. It is suggested that high-functioning dyslexics may cope with temporal processing problems by adopting a predominantly holistic, orthographic strategy when decoding. It is proposed that there may be cumulative effects of processing demands from different sources including modality, stimulus complexity, and linguistic demands, and that combinations of these may interact to impact temporal processing ability. Moreover, there may be fundamentally distinct and dissociable temporal processing abilities, each of which may be differently linked developmental dyslexia. Copyright © 2005 John Wiley & Sons, Ltd. [source] Effects of environmental perturbations on abundance of subarctic plants after three, seven and ten years of treatmentsECOGRAPHY, Issue 1 2001Enrico Graglia Analyses of changes in vegetation were carried out after three, seven and ten years of fertilizer addition, warming and light attenuation in two subarctic, alpine dwarf shrub heaths. One site was just above the tree line, at ca 450 m a.s.l., and the other at a much colder fell-field at ca 1150 m altitude. The aim was to investigate how the treatments affected the abundance of different species and growth forms over time, including examinations of transient changes. Grasses, which increased in abundance by fertilizer addition, and cryptogams, which, by contrast, decreased by fertilizer addition and warming, were the most sensitive functional groups to the treatments at both sites. Nutrient addition exerted a stronger and more consistent effect than both shading and warming. Warming at the fell-field had slightly greater effect than at the warmer tree line with an increase in deciduous shrubs. The decreased abundance of mosses and lichens to fertilizer addition and/or warming was most likely an indirect treatment effect, caused by competition through increased abundance and overgrowth of grasses. Such changes in species composition are likely to alter decomposition rates and the water and energy exchange at the soil surface. We observed few, if any, transient effects of declining responses during the 10 yr of treatments. Instead, there were many cumulative effects of the treatments for all functional groups and many interactions between time and treatment, suggesting that once a change in community composition is triggered, it will continue with unchanged or accelerated rate for a long period of time. [source] Inter-sexual differences in the immune response of Eurasian kestrel nestlings under food shortageECOLOGY LETTERS, Issue 1 2002Juan A. Fargallo When resources are limited, parents should decide the optimal number, size, and sex of progeny, and offspring should decide the optimal allocation of resources to different costly functions, such as growth and immunity. We manipulated clutch sizes of Eurasian kestrels by one egg to estimate possible cumulative effects of incubation and chick rearing costs on parental body condition, feeding effort, and offspring viability. No obvious effects of clutch size manipulations on feeding effort were found while feeding effort was adjusted to the original clutch size. Enlarged and control nests suffered from higher nestling mortality than reduced nests, and chicks of the enlarged group were in poorer body condition than chicks of the reduced group. Controlling for body mass, male chicks exhibited lower cell-mediated immunity assessed by a cutaneous hypersensitivity response than females, but only in treatments suffering from food restrictions, as indicated by chick starvation. These novel results reveal inter-sexual differences in physiological strategies in early life, suggesting sex-related differences in susceptibility to disease and consequently in survival prospects of offspring. [source] Problem gamblers share deficits in impulsive decision-making with alcohol-dependent individualsADDICTION, Issue 6 2009Andrew J. Lawrence ABSTRACT Aims Problem gambling has been proposed to represent a ,behavioural addiction' that may provide key insights into vulnerability mechanisms underlying addiction in brains that are not affected by the damaging effects of drugs. Our aim was to investigate the neurocognitive profile of problem gambling in comparison with alcohol dependence. We reasoned that shared deficits across the two conditions may reflect underlying vulnerability mechanisms, whereas impairments specific to alcohol dependence may reflect cumulative effects of alcohol consumption. Design Cross-sectional study. Setting Out-patient addiction treatment centres and university behavioural testing facilities. Participants A naturalistic sample of 21 male problem and pathological gamblers, 21 male alcohol-dependent out-patients and 21 healthy male control participants. Measurements Neurocognitive battery assessing decision-making, impulsivity and working memory. Findings The problem gamblers and alcohol-dependent groups displayed impairments in risky decision-making and cognitive impulsivity relative to controls. Working memory deficits and slowed deliberation times were specific to the alcohol-dependent group. Conclusions Gambling and alcohol-dependent groups shared deficits in tasks linked to ventral prefrontal cortical dysfunction. Tasks loading on dorsolateral prefrontal cortex were selectively impaired in the alcohol-dependent group, presumably as a consequence of long-term alcohol use. [source] Risk assessment of Magnacide® H herbicide at Río Colorado irrigation channels (Argentina). tier 3: Studies on native speciesENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2007Andrés Venturino Abstract We evaluated the potential environmental risk of the herbicide Magnacide® (Baker Petrolite, TX, USA) using native species from Argentina, representing the ecosystem at the Irrigation Corporation (CORFO) channels at the Colorado River mouth, Buenos Aires, Argentina. Six species including fish, toads, snails, crustaceans, and insects were selected to perform studies on acute toxicity and repeated exposure effects. Magnacide H susceptibility ranking was Bufo arenarum (lethal concentration 50 [LC50] = 0.023 mg/L), Onchorhynchus mykiss (LC50 = 0.038 mg/L), Heleobia parchappii (LC50 = 0.21 mg/L), Hyalella curvispina (LC50 = 0.24 mg/L), Simulium spp. (LC50 = 0.60 mg/L), and Chironomus spp. (LC50 = 2.83 mg/L). The risk limit of 10th percentile (0.013 mg/L) determined by probit analysis on sensitivity distribution was similar to the one calculated from literature data. Risk assessment based on field application data suggested lethal exposures for more than 70 to 90% of the species up to 20 km downstream from the application point. Repeated exposures to Magnacide H of amphibian larvae at the lowest-observed-effect concentration caused some effects during the first exposure, but without cumulative effects. Amphipods were insensitive to repeated exposures, showing no cumulative effects. Whether short-term exposures may result in long-term sublethal effects on the organism's life history was not addressed by these laboratory tests. In conclusion, tier 3 studies indicate that Magnacide H application schedule is extremely toxic for most native species at CORFO,Río Colorado channels, representing a high potential risk in the environment. The real environmental impact must be addressed by field studies at tier 4 giving more information on population effects and communities. [source] Aquatic herbicide exposure increases salamander desiccation risk eight months later in a terrestrial environmentENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2005Jason R. Rohr Abstract Contaminants and climate change may be factors in amphibian declines. However, few studies have explored their joint impacts on postmetamorphic amphibians, a life stage of great importance to amphibian population dynamics. Here, we examine the effects of premetamorphic exposure (mean exposure of 64 d) to ecologically relevant concentrations of the globally common herbicide atrazine (0, 4, 40, 400 ,g/L) on the behavior and water retention of lone and grouped postmetamorphic, streamside salamanders, Ambystoma barbouri. Salamanders exposed to ,40 ,g/L of atrazine exhibited greater activity, fewer water-conserving behaviors, and accelerated water loss four and eight months after exposure compared to controls. No recovery from atrazine exposure was detected and its effects were independent of the presence of conspecifics. These results are consistent with the hypothesis that adverse climatic conditions and contaminants can interact to harm post-metamorphic amphibians; however, they suggest that these two stressors need not be experienced simultaneously to do so. These results emphasize the importance of considering both latent and cumulative effects of temporally linked stressors in ecotoxicology. [source] Physiological responses of two contrasting desert plant species to precipitation variability are differentially regulated by soil moisture and nitrogen dynamicsGLOBAL CHANGE BIOLOGY, Issue 5 2009LISA D. PATRICK Abstract Alterations in global and regional precipitation patterns are expected to affect plant and ecosystem productivity, especially in water-limited ecosystems. This study examined the effects of natural and supplemental (25% increase) seasonal precipitation on a sotol grassland ecosystem in Big Bend National Park in the Chihuahuan Desert. Physiological responses , leaf photosynthesis at saturating light (Asat), stomatal conductance (gs), and leaf nitrogen [N] , of two species differing in their life form and physiological strategies (Dasylirion leiophyllum, a C3 shrub; Bouteloua curtipendula, a C4 grass) were measured over 3 years (2004,2006) that differed greatly in their annual and seasonal precipitation patterns (2004: wet, 2005: average, 2006: dry). Precipitation inputs are likely to affect leaf-level physiology through the direct effects of altered soil water and soil nitrogen. Thus, the effects of precipitation, watering treatment, soil moisture, and nitrogen were quantified via multivariate hierarchical Bayesian models that explicitly linked the leaf and soil responses. The two species differed in their physiological responses to precipitation and were differentially controlled by soil water vs. soil nitrogen. In the relatively deeply rooted C3 shrub, D. leiophyllum, Asat was highest in moist periods and was primarily regulated by deep (16,30 cm) soil water. In the shallow-rooted C4 grass, B. curtipendula, Asat was only coupled to leaf [N], both of which increased in dry periods when soil [N] was highest. Supplemental watering during the wet year generally decreased Asat and leaf [N] in D. leiophyllum, perhaps due to nutrient limitation, and physiological responses in this species were influenced by the cumulative effects of 5 years of supplemental watering. Both species are common in this ecosystem and responded strongly, yet differently, to soil moisture and nitrogen, suggesting that changes in the timing and magnitude of precipitation may have consequences for plant carbon gain, with the potential to alter community composition. [source] Tidal Barrages and BirdsIBIS, Issue 2006NIGEL A. CLARK This paper reviews the main effects that building tidal power barrages would have on the bird populations using Britain's estuaries. The changes in the tidal prism that would occur after a tidal power barrage is built are discussed in the context of their effect on the ecology of the estuary. Three main issues are discussed; the effect of changes in size and nature of the intertidal areas of the estuary, effects on saltmarshes, and the displacement of birds at closure. Recently, tidal stream technologies have been developed which are individually likely to have small effects on birds. However the cumulative effects of large scale tidal stream arrays need to be investigated. Finally, the effects of tidal barrages are put in the context of Britain's energy policy and the need to reduce greenhouse gas emissions. Should tidal power barrages be considered in the future, there will be a need for strategic assessments to be used to select sites that maximize the energy produced while minimizing the impacts on bird populations. [source] The potential for Toll-like receptors to collaborate with other innate immune receptorsIMMUNOLOGY, Issue 4 2004Subhankar Mukhopadhyay Summary Cells of the innate immune system express a large repertoire of germ-line encoded cell-surface glycoprotein receptors including Toll-like receptors (TLRs). TLRs recognize conserved motifs on microbes and induce inflammatory signals. Evidence suggests that individual members of the TLR family or other non-TLR surface antigens either physically or functionally interact with each other and cumulative effects of these interactions instruct the nature and outcome of the immune response to a particular pathogen. [source] Cumulative effects of in utero administration of mixtures of reproductive toxicants that disrupt common target tissues via diverse mechanisms of toxicityINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 2 2010C. V. Rider Summary Although risk assessments are typically conducted on a chemical-by-chemical basis, the 1996 Food Quality Protection Act required the US Environmental Protection Agency to consider cumulative risk of chemicals that act via a common mechanism of toxicity. To this end, we are conducting studies with mixtures of chemicals to elucidate mechanisms of joint action at the systemic level with the goal of providing a framework for assessing the cumulative effects of reproductive toxicants. Previous mixture studies conducted with antiandrogenic chemicals are reviewed briefly and two new studies are described. In all binary mixture studies, rats were dosed during pregnancy with chemicals, singly or in pairs, at dosage levels equivalent to approximately one-half of the ED50 for hypospadias or epididymal agenesis. The binary mixtures included androgen receptor (AR) antagonists (vinclozolin plus procymidone), phthalate esters [di(n-butyl) phthalate (DBP) plus benzyl n-butyl phthalate (BBP) and diethyl hexyl phthalate (DEHP) plus DBP], a phthalate ester plus an AR antagonist (DBP plus procymidone), a mixed mechanism androgen signalling disruptor (linuron) plus BBP, and two chemicals which disrupt epididymal differentiation through entirely different toxicity pathways: DBP (AR pathway) plus 2,3,7,8 TCDD (AhR pathway). We also conducted multi-component mixture studies combining several ,antiandrogens'. In the first study, seven chemicals (four pesticides and three phthalates) that elicit antiandrogenic effects at two different sites in the androgen signalling pathway (i.e. AR antagonist or inhibition of androgen synthesis) were combined. In the second study, three additional phthalates were added to make a 10 chemical mixture. In both the binary mixture studies and the multi-component mixture studies, chemicals that targeted male reproductive tract development displayed cumulative effects that exceeded predictions based on a response-addition model and most often were in accordance with predictions based on dose-addition models. In summary, our results indicate that compounds that act by disparate mechanisms of toxicity to disrupt the dynamic interactions among the interconnected signalling pathways in differentiating tissues produce cumulative dose-additive effects, regardless of the mechanism or mode of action of the individual mixture component. [source] Transgenic expression of CCK2 receptors sensitizes murine pancreatic acinar cells to carcinogen-induced preneoplastic lesions formationINTERNATIONAL JOURNAL OF CANCER, Issue 1 2005Anne Mathieu Abstract In humans, initial events of pancreatic carcinogenesis remain unknown, and the question of whether this cancer, which has a ductal phenotype, exclusively arises from duct cells has been raised. Previous studies have demonstrated that transgenic expression of the CCK2 receptor in acinar cells of ElasCCK2 mice plays a role in the development of pancreatic neoplasia. The aim of our study was to examine initial steps of carcinogenesis in ElasCCK2 mice, adding a supplementary defect by using a chemical carcinogen, azaserine. Results of posttreatment sequential immunohistochemical examinations and quantifications demonstrate that mice responded to azaserine. Transition of acinar cells into duct-like cells expressing Pdx1 and gastrin, as well as proliferation of acinar cells, were transiently observed in both transgenic and control mice. The carcinogen also induced formation of preneoplastic lesions, adenomas, exhibiting properties of autonomous growth. Importantly, expression of the CCK2 receptor increased the susceptibility of pancreas to azaserine. Indeed, treated ElasCCK2 mice exhibited larger areas of pancreatic acinar-ductal transition, increased cellular proliferation as well as larger adenomas areas vs. control mice. These amplified responses may be related to auto/paracrine stimulation of CCK2 receptor by gastrin expressed in newly formed duct-like cells. Our results demonstrate that activation of CCK2 receptor and azaserine result in cumulative effects to favor the emergence of a risk situation that is a potential site for initiation of carcinogenesis. © 2005 Wiley-Liss, Inc. [source] Growth of functional cranial components in rats submitted to intergenerational undernutritionJOURNAL OF ANATOMY, Issue 2 2006María F. Cesani Abstract The aim of the present study was to discover how intergenerational undernutrition affects the growth of major and minor functional cranial components in two generations of rats. Control animals constituted the parental generation (P). The undernourished generations (F1 and F2) were fed 75% of the control diet. Animals were X-rayed every 10 days from 20 to 100 days of age. The length, width and height of the major (neurocranium and splanchnocranium) and minor (anterior-neural, middle-neural, posterior-neural, otic, respiratory, masticatory and alveolar) cranial components were measured on each radiograph. Volumetric indices were calculated to estimate size variations of these components. Data were processed using the Kruskal,Wallis and Kolmogorov,Smirnov tests for two samples. Impairment in splanchnocranial and neurocranial growth was found, the latter being more affected than the former in F1. Comparison between F2 and F1 animals showed cumulative effects of undernutrition in both major and minor components (anterior-neural, respiratory, masticatory and alveolar in males, and middle-neural and respiratory in females). Such differential effects on minor components may reflect a residual mechanical strain resulting from the linkage between components. This phenomenon was clearly observed in the neurocranium and could be understood as an adaptive response to the demands of the associated functional matrices. [source] Large-scale ecology and hydrology: an introductory perspective from the editors of the Journal of Applied EcologyJOURNAL OF APPLIED ECOLOGY, Issue 2000S.J. Ormerod 1. Five key features characterize large-scale factors in ecology: (a) they incorporate some of the most major of all ecological phenomena , the ranges of organisms, patterns of diversity, variations in ecosystem character and environmental processes such as climate, biogeochemical cycles, dispersal and migration; (b) they involve interactions across scales through both top-down and bottom-up processes; (c) they are multifaceted, and hence require an interdisciplinary perspective; (d) they reflect the cumulative effects of anthropogenic change across all scales, and so have direct relevance to environmental management; (e) they invariably exceed the range of classical ecological experiments, and so require alternative approaches to hypothesis testing. 2. Against this background, a recent research initiative on large-scale ecology and hydrology was funded jointly by the Natural Environment Research Council (NERC) and the Scottish Executive Rural Affairs Department (SERAD). Outputs from this programme are reported in this special issue of the Journal of Applied Ecology, and they illustrate some of the ecological research that is currently in progress in the UK at large spatio-temporal scales. 3. The spatial scales investigated in the papers range from hectares to whole continents, and much of the work reported here involves modelling. Although the model outputs are intrinsically valuable, several authors express the need for improved validation and testing. We suggest that this is an area requiring much development, and will need considerable innovation due to the difficulties at the scales involved (see 1d). Possible methods include: model applications to new circumstances; large-scale environmental manipulations; large-scale surveys that mimic experimental protocols; support from process studies at smaller scales. These alternatives are not mutually exclusive, and all can allow robust hypothesis testing. 4. Much of the work reported here is interdisciplinary linking, for example, geographical, mathematical, hydrological, hydrochemical and ecological concepts (see 1c). We suggest that even stronger links between environmental disciplines will further aid large-scale ecological research. 5. Most important in the context of the Journal of Applied Ecology, the work reported in this issue reveals that large-scale ecology already has applied value. Sectors benefiting include the conservation of biodiversity, the control of invasive species, and the management of land and water resources. 6. Large-scale issues continue to affect many applied ecologists, with roughly 30,40% of papers published in the Journal of Applied Ecology typically confronting such problems. This special issue adds to the growing body of seminal contributions that will add impetus to further large-scale work. Moreover, occurring in a period when other areas of biology are increasingly reductionist, this collection illustrates that, at least with respect to large-scale environmental problems, ecology still holds centre ground. [source] Promoting adolescent sense of coherence: Testing models of risk, protection, and resiliencyJOURNAL OF COMMUNITY & APPLIED SOCIAL PSYCHOLOGY, Issue 1 2010William Paul Evans Abstract Sense of coherence (SOC) is a dispositional trait that has been linked to well-being in a broad range of populations and contexts. Little is known, however, about the factors associated with SOC development and maintenance across the lifespan. Conceptualized as a condition of resiliency, SOC in adolescents was explored via measures of risk and protection as reported on by 8th and 10th grade students (N,=,1619). Employing cumulative indexes of protection and risk, analyses focused on testing four models of resiliency. Further, the relative and cumulative effects of protection and risk were explored across ecological domains. Analyses revealed support for the compensatory model of resiliency for males and females, while the challenge model also was supported for females. Analyses also revealed that protection and risk influencing SOC emerge at multiple domains for males and females. In addition, protective factors present at multiple domains were related to higher SOC while risk factors present at multiple domains were related to lower SOC regardless of gender. Results suggest a resiliency framework that considers multiple ecological domains is useful for understanding SOC in adolescents. Implications for additional research are presented. Copyright © 2008 John Wiley & Sons, Ltd. [source] Interactions between gnathiid isopods, cleaner fish and other fishes on Lizard Island, Great Barrier ReefJOURNAL OF FISH BIOLOGY, Issue 9 2008A. S. Grutter The rate of emergence of micropredatory gnathiid isopods from the benthos, the proportion of emerging gnathiids potentially eaten by Labroides dimidiatus, and the volume of blood that gnathiids potentially remove from fishes (using gnathiid gut volume) were determined. The abundance (mean ±s.e.) of emerging gnathiids was 41·7 ± 6·9 m,2 day,1 and 4552 ± 2632 reef,1 day,1 (reefs 91,125 m2). The abundance of emerging gnathiids per fish on the reef was 4·9 ± 0·8 day,1; but excluding the rarely infested pomacentrid fishes, it was 20·9 ± 3·8 day,1. The abundance of emerging gnathiids per patch reef was 66 ± 17% of the number of gnathiids that all adult L. dimidiatus per reef eat daily while engaged in cleaning behaviour. If all infesting gnathiids subsequently fed on fish blood, their total gut volume per reef area would be 17·4 ± 5·6 mm3 m,2 day,1; and per fish on the reefs, it would be 2·3 ± 0·5 mm,3 fish,1 day,1 and 10·3 ± 3·1 mm3 fish,1 day,1 (excluding pomacentrids). The total gut volume of gnathiids infesting caged (137 mm standard length, LS) and removed from wild (100,150 mm LS) Hemigymnus melapterus by L. dimidiatus was 26·4 ± 24·6 mm3 day,1 and 53·0 ± 9·6 mm3 day,1, respectively. Using H. melapterus (137 mm LS, 83 g) as a model, gnathiids had the potential to remove, 0·07, 0·32, 0·82 and 1·63% of the total blood volume per day of each fish, excluding pomacentrids, caged H. melapterus and wild H. melapterus, respectively. In contrast, emerging gnathiids had the potential of removing 155% of the total blood volume of Acanthochromis polyacanthus (10·7 mm LS, 0·038 g) juveniles. That L. dimidiatus eat more gnathiids per reef daily than were sampled with emergence traps suggests that cleaner fishes are an important source of mortality for gnathiids. Although the proportion of the total blood volume of fishes potentially removed by blood-feeding gnathiids on a daily basis appeared to be low for fishes weighing 83 g, the cumulative effects of repeated infections on the health of such fish remains unknown; attacks on small juvenile fishes, may result in possibly lethal levels of blood loss. [source] Long-term effects of imidacloprid on the abundance of surface- and soil-active nontarget fauna in turfAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 4 2009Daniel C. Peck Abstract 1Outbreaks of root-feeding scarab larvae in turfgrass are widely managed through preventive applications of imidacloprid. Long-residual activity and application before feasible scouting probably lead to its overuse and overexposure. 2Recent investigations revealed a selective impact of imidacloprid (not trichlorfon or halofenozide) on certain nontarget turf arthropods, motivating the present study on the persistence of abundance effects over 6 years of annual applications. 3Arthropods were sampled monthly (July to October) in replicated plots using soil core heat extraction and pitfall traps to quantify soil- and surface-active arthropods. Captures were identified to class, order or family. The most represented taxa were analysed to test for cumulative effects and their change over season and year. 4Imidacloprid had no impact on pitfall captures, although the abundance of Hemiptera, Thysanoptera, Coleoptera and Collembola was suppressed in soil core captures. Among beetles, impact was expressed in adults (not larvae), and in Carabidae and Staphylinidae (not Chrysomelidae or Curculionidae). Among springtails, impact was expressed in Entomobryomorpha (not Poduromorpha or Symphypleona). Impact did not diminish with year but there was variable recovery between applications. 5There may therefore be a diverging response of soil- and surface-active fauna to the nontarget impacts of imidacloprid. The suppression of predaceous (not phytophagous) beetles indicates an indirect effect mediated through declines in prey populations. 6The magnitude of abundance effects confirms that the balance between target and nontarget impact should be explicitly examined. Implications are discussed with respect to functional relevance for nutrient cycling and the natural regulation of pests. [source] Principal-component analysis of multiscale data for process monitoring and fault diagnosisAICHE JOURNAL, Issue 11 2004Seongkyu Yoon Abstract An approach is presented to multivariate statistical process control (MSPC) for process monitoring and fault diagnosis based on principal-component analysis (PCA) models of multiscale data. Process measurements, representing the cumulative effects of many underlying process phenomena, are decomposed by applying multiresolution analysis (MRA) by wavelet transformations. The decomposed process measurements are rearranged according to their scales, and PCA is applied to these multiscale data to capture process variable correlations occurring at different scales. Choosing an orthonormal mother wavelet allows each principal component to be a function of the process variables at only one scale level. The proposed method is discussed in the context of other multiscale approaches, and illustrated in detail using simulated data from a continuous stirred tank reactor (CSTR) system. A major contribution of the paper is to extend fault isolation methods based on contribution plots to multiscale approaches. In particular, once a fault is detected, the contributions of the variations at each scale to the fault are computed. These scale contributions can be very helpful in isolating faults that occur mainly at a single scale. For those scales having large contributions to the fault, one can further compute the variable contributions to those scales, thereby making fault diagnosis much easier. A comparison study is done through Monte Carlo simulation. The proposed method can enhance fault detection and isolation (FDI) performance when the frequency content of a fault effect is confined to a narrow-frequency band. However, when the fault frequency content is not localized, the multiscale approaches perform very comparably to the standard single-scale approaches, and offer no real advantage. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2891,2903, 2004 [source] Addressing Three Common Issues in Research on Youth Activities: An Integrative Approach for Operationalizing and Analyzing InvolvementJOURNAL OF RESEARCH ON ADOLESCENCE, Issue 3 2010Michael A. Busseri Youth activity involvement has been operationalized and analyzed using a wide range of approaches. Researchers face the challenges of distinguishing between the effects of involvement versus noninvolvement and intensity of involvement in a particular activity, accounting simultaneously for cumulative effects of involvement, and addressing multiple unique effects of individual activities. In the present work, we review and illustrate the conceptual and empirical implications of these issues using data from a study of activity involvement and successful development in early adolescence (N=537; M age=11.56, 52% female). An integrative solution is introduced based on a latent composite variable (LCV) model (Bollen & Lennox, 1991), which can be used to address all three issues simultaneously. Using this approach, we show that of the aggregate indices examined, breadth of involvement was uniquely and positively associated with multiple indices of successful development. Of the individual activities, a dichotomous score and residual frequency rating for involvement in out-of-school clubs were both uniquely associated with less positive development indicators. We concluded that an LCV approach provides a novel method for addressing several fundamental operational and analytic issues facing researchers who investigate youth activity involvement as a context for positive development. [source] XRCC4 codon 247*A and XRCC4 promoter ,1394*T related genotypes but not XRCC4 intron 3 gene polymorphism are associated with higher susceptibility for endometriosis,MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 5 2008Yao-Yuan Hsieh Abstract DNA repair systems act to maintain genome integrity in the face of replication errors, environmental insults, and the cumulative effects of age. Genetic variants in DNA repair genes such as X-ray repair cross-complementing group 4 (XRCC4) might influence the ability to repair damaged DNA. Herein we aimed to investigate whether some XRCC4-related polymorphisms were associated with endometriosis susceptibility. Women were divided: (1) severe endometriosis (rAFS stage IV, n,=,136) and (2) nonendometriosis groups (n,=,112). The polymorphisms of XRCC4 codon 247, XRCC4 promoter ,1394, and XRCC4 intron 3 insertion/deletion (I/D) polymorphism were amplified by PCR and detected by electrophoresis after restriction enzyme (BBS I, Hinc II) digestions. Genotypes and allelic frequencies in both groups were compared. We observed that XRCC4 codon 247*A and XRCC4 promoter ,1394*T related genotypes, but not XRCC4 intron 3 I/D polymorphism, are associated with higher susceptibility for endometriosis. Distributions of XRCC4 codon 247*C homozygote/heterozygote/A homozygote, and C/A allele in both groups were: (1) 89/9.5/1.5% and 93.7/6.3%; (2) 97.3/2.7/0%, and 98.7/1.3% (P,<,0.05). Proportions of XRCC4 promoter ,1394*T homozygote/heterozygote/G homozygote and T/G allele in both groups were: (1) 94.1/5.2/0.7% and 96.7/3.3%, and (2) 79.4/17.9/2.7% and 88.4/11.6% (P,<,0.005). Proportions of XRCC4*I homozygote/heterozygote/D homozygote and A/C allele in both groups were: (1) 67.6/30.9/1.5% and 83.2/16.8%, and (2) 70.5/24.1/5.4% and 82.6/17.4% (nondifference). We conclude that XRCC4 codon 247*A and XRCC4 promoter ,1394*T related genotypes and alleles, but not XRCC4 intron 3 I/D polymorphism, might be associated with endometriosis susceptibilities and pathogenesis. Mol. Reprod. Dev. 75: 946,951, 2008. © 2008 Wiley-Liss, Inc. [source] Factors contributing to decreased protein stability when aspartic acid residues are in ,-sheet regionsPROTEIN SCIENCE, Issue 7 2002P.R. Pokkuluri Abstract Asp residues are significantly under represented in ,-sheet regions of proteins, especially in the middle of ,-strands, as found by a number of studies using statistical, modeling, or experimental methods. To further understand the reasons for this under representation of Asp, we prepared and analyzed mutants of a ,-domain. Two Gln residues of the immunoglobulin light-chain variable domain (VL) of protein Len were replaced with Asp, and then the effects of these changes on protein stability and protein structure were studied. The replacement of Q38D, located at the end of a ,-strand, and that of Q89D, located in the middle of a ,-strand, reduced the stability of the parent immunoglobulin VL domain by 2.0 kcal/mol and 5.3 kcal/mol, respectively. Because the Q89D mutant of the wild-type VL -Len domain was too unstable to be expressed as a soluble protein, we prepared the Q89D mutant in a triple mutant background, VL -Len M4L/Y27dD/T94H, which was 4.2 kcal/mol more stable than the wild-type VL -Len domain. The structures of mutants VL -Len Q38D and VL -Len Q89D/M4L/Y27dD/T94H were determined by X-ray diffraction at 1.6 Å resolution. We found no major perturbances in the structures of these Q,D mutant proteins relative to structures of the parent proteins. The observed stability changes have to be accounted for by cumulative effects of the following several factors: (1) by changes in main-chain dihedral angles and in side-chain rotomers, (2) by close contacts between some atoms, and, most significantly, (3) by the unfavorable electrostatic interactions between the Asp side chain and the carbonyls of the main chain. We show that the Asn side chain, which is of similar size but neutral, is less destabilizing. The detrimental effect of Asp within a ,-sheet of an immunoglobulin-type domain can have very serious consequences. A somatic mutation of a ,-strand residue to Asp could prevent the expression of the domain both in vitro and in vivo, or it could contribute to the pathogenic potential of the protein in vivo. [source] Appraisal of the cancer experience by older long-term survivorsPSYCHO-ONCOLOGY, Issue 3 2003Karen F. Bowman Cancer survivorship is best viewed as a process that continues across the life span. Appraisals of cancer change over time and may not be explicit until long after treatment completion. The current study, using the Lazarus and Folkman (1984) stress-appraisal-coping framework, explored factors related to both a stressful and an irrelevant appraisal of the cancer experience by older long-term survivors. Hierarchical regression analysis investigated the individual and cumulative effects of person factors (survivors' demographic characteristics, beliefs about the effect of cancer on family members) and situation factors (characteristics of cancer) on survivors' appraisals that cancer was a stressful life event. The strongest correlates of the stress appraisal were person factors. A more stressful appraisal was associated with: (1) the belief that diagnosis/treatment caused greater family distress, (2) being younger, and (3) being White. The irrelevant appraisal had a marginally significant correlate in bivariate analysis and was not included in regression analysis. Implications for health-care professionals and patient/family interventions are discussed. Copyright © 2002 John Wiley & Sons, Ltd. [source] Stretch Goals and Backcasting: Approaches for Overcoming Barriers to Large-Scale Ecological RestorationRESTORATION ECOLOGY, Issue 4 2006Adrian D. Manning Abstract The destruction and transformation of ecosystems by humans threatens biodiversity, ecosystem function, and vital ecosystem services. Ecological repair of ecosystems will be a major challenge over the next century and beyond. Restoration efforts to date have frequently been ad hoc, and site or situation specific. Although such small-scale efforts are vitally important, without large-scale visions and coordination, it is unlikely that large functioning ecosystems will ever be constructed by chance through the cumulative effects of small-scale projects. Although the problems of human-induced environmental degradation and the need for a solution are widely recognized, these issues have rarely been addressed on a sufficiently large-scale basis. There are numerous barriers that prevent large-scale ecological restoration projects from being proposed, initiated, or carried through. Common barriers include the "shifting baseline syndrome," the scale and complexity of restoration, the long-term and open-ended nature of restoration, funding challenges, and preemptive constraint of vision. Two potentially useful approaches that could help overcome these barriers are stretch goals and backcasting. Stretch goals are ambitious long-term goals used to inspire creativity and innovation to achieve outcomes that currently seem impossible. Backcasting is a technique where a desired end point is visualized, and then a pathway to that end point is worked out retrospectively. A case study from the Scottish Highlands is used to illustrate how stretch goals and backcasting could facilitate large-scale restoration. The combination of these approaches offers ways to evaluate and shape options for the future of ecosystems, rather than accepting that future ecosystems are victims of past and present political realities. [source] Covariance-oriented qualitative and quantitative calibration analysis for multistage batch processesTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2009Chunhui Zhao Abstract An improved stage-specific multivariate calibration scheme is developed for multistage batch processes based on the covariance analysis unit. First, the process duration is automatically and properly divided into different stages, which reveals the changes of quality-related process correlation characteristics. The concept of stage-representative average process behaviour is then introduced, which is comprehensibly realized by averaging all covariance patterns within the same stage based on different weights. In this way, it stacks the cumulative effects of process variations on quality within each stage and meanwhile considers their time-varying characteristics. Subsequently, covariance-oriented OSC and variable selection are effectively combined, which can simplify the calibration model structure and enhance the causal relationship between predictors and quality by excluding the redundant latent factors and input variables. Finally, stage-representative PLS regression models are developed focusing on the critical-to-quality stages for online quality prediction. It shows that a complete multistage calibration solution is readily achieved from an "overall" stage perspective by smartly making use of covariance. The illustration study to injection molding shows the effectiveness of the proposed method for improving process comprehension and quality prediction. On a mis au point un schéma amélioré d'étalonnage multivarié pour des procédés discontinus multi-étapes, spécifique à chaque étape, basé sur l'analyse des covariances sans tenir compte de chaque variable de procédé. En premier lieu, la durée de procédé est automatiquement et correctement divisée en quatre étapes différentes, révélant le changement des caractéristiques de corrélation de procédé lié à la qualité. Le concept de comportement de procédé moyen représentatif d'une étape est alors introduit, ce qui se réalise de façon complète en moyennant tous les profils de covariance d'une étape donnée avec différentes pondérations. De cette façon, on tient compte dans la qualité des effets cumulatifs des variations de procédé spécifiques à chaque étape et considère de ce fait leurs caractéristiques évolutives. Par conséquent, l'OSC orienté vers la covariance et la technique de sélection des variables sont combinés efficacement afin de simplifier la structure du modèle d'étalonnage et améliorer la relation causale en excluant les facteurs latents redondants ou les variables d'entrée. Enfin, des modèles de régression de type PLS représentatifs des étapes sont mis au point, mettant l'accent sur les étapes critiques en terme de qualité pour la prédiction de la qualité en ligne. Cela montre qu'une solution complète d'étalonnage multi-étapes peut se réaliser parfaitement en utilisant bien la covariance. L'illustration dans le cas du moulage par injection montre l'efficacité de la méthode proposée pour la compréhension du procédé et l'amélioration des prédictions. [source] Effect of anthropogenic low-frequency noise on the foraging ecology of Balaenoptera whalesANIMAL CONSERVATION, Issue 1 2001Donald A. Croll The human contribution to ambient noise in the ocean has increased over the past 50 years, and is dominated by low-frequency (LF) sound (frequencies <1000 Hz) from shipping, oil and gas development, defence-related and research activities. Mysticete whales, including six endangered species, may be at risk from this noise pollution because all species produce and probably perceive low-frequency sound. We conducted a manipulative field experiment to test the effects of loud, LF noise on foraging fin blue (B. musculus) and (Balaenoptera physalus) whales off San Nicolas Island, California. Naive observers used a combination of attached tracking devices, ship-based surveys, aerial surveys, photo-identification and passive monitoring of vocal behaviour to examine the behaviour and distribution of whales when a loud LF source (US Navy SURTASS LFA) was and was not transmitting. During transmission, 12-30% of the estimated received levels of LFA of whales in the study area exceeded 140 dB re 1 ,Pa. However, whales continued to be seen foraging in the region. Overall, whale encounter rates and diving behaviour appeared to be more strongly linked to changes in prey abundance associated with ceanographic parameters than to LF sound transmissions. In some cases, whale vocal behaviour was significantly different between experimental and non-experimental periods. However, these differences were not consistent and did not appear to be related to LF sound transmissions. At the spatial and temporal scales examined, we found no obvious responses of whales to a loud, anthropogenic, LF sound. We suggest that the cumulative effects of anthropogenic LF noise over larger temporal and spatial scales than examined here may be a more important consideration for management agencies. [source] | |||||||||||||||||||||||||||||||||||||