131 research outputs found

    User Adaptive Answers Generation for Conversational Agent Using Genetic Programming

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    Abstract. Recently, it seems to be interested in the conversational agent as an effective and familiar information provider. Most of conversational agents reply to user’s queries based on static answers constructed in advance. Therefore, it cannot respond with flexible answers adjusted to the user, and the stiffness shrinks the usability of conversational agents. In this paper, we propose a method using genetic programming to generate answers adaptive to users. In order to construct answers, Korean grammar structures are defined by BNF (Backus Naur Form), and it generates various grammar structures utilizing ge-netic programming (GP). We have applied the proposed method to the agent in-troducing a fashion web site, and certified that it responds more flexibly to user’s queries.

    Étude de la motricité du rumen chez les petits ruminants VI. — Influence de l’ingestion d’urée

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    Annicolas D., Le Bars Henri, Nugues J., Simonnet Henri. Étude de la motricité du rumen chez les petits ruminants VI. — Influence de l’ingestion d’urée. In: Bulletin de l'Académie Vétérinaire de France tome 109 n°5, 1956. pp. 257-261

    Toxicité de l’urée chez les petits ruminants

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    Annicolas D., Le Bars Henri, Nugues J., Simonnet Henri. Toxicité de l’urée chez les petits ruminants. In: Bulletin de l'Académie Vétérinaire de France tome 109 n°5, 1956. pp. 225-232

    Impact and amelioration of sediment pollution on coral reefs of St. Lucia, West Indies

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    Includes Policy and Management Brief 1: Annex A2.# Appendix 1 of the Final Technical Report of project R766

    Local human impacts disrupt relationships between benthic reef assemblages and environmental predictors

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    Human activities are changing ecosystems at an unprecedented rate, yet large-scale studies into how local human impacts alter natural systems and interact with other aspects of global change are still lacking. Here we provide empirical evidence that local human impacts fundamentally alter relationships between ecological communities and environmental drivers. Using tropical coral reefs as a study system, we investigated the influence of contrasting levels of local human impact using a spatially extensive dataset spanning 62 outer reefs around inhabited Pacific islands. We tested how local human impacts (low versus high determined using a threshold of 25 people km−2 reef) affected benthic community (i) structure, and (ii) relationships with environmental predictors using pre-defined models and model selection tools. Data on reef depth, benthic assemblages, and herbivorous fish communities were collected from field surveys. Additional data on thermal stress, storm exposure, and market gravity (a function of human population size and reef accessibility) were extracted from public repositories. Findings revealed that reefs subject to high local human impact were characterised by relatively more turf algae (>10% higher mean absolute coverage) and lower live coral cover (9% less mean absolute coverage) than reefs subject to low local human impact, but had similar macroalgal cover and coral morphological composition. Models based on spatio-physical predictors were significantly more accurate in explaining the variation of benthic assemblages at sites with low (mean adjusted-R2 = 0.35) rather than high local human impact, where relationships became much weaker (mean adjusted-R2 = 0.10). Model selection procedures also identified a distinct shift in the relative importance of different herbivorous fish functional groups in explaining benthic communities depending on the local human impact level. These results demonstrate that local human impacts alter natural systems and indicate that projecting climate change impacts may be particularly challenging at reefs close to higher human populations, where dependency and pressure on ecosystem services are highest

    In Situ Oxygen Dynamics in Coral-Algal Interactions

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    Background: Coral reefs degrade globally at an alarming rate, with benthic algae often replacing corals. However, the extent to which benthic algae contribute to coral mortality, and the potential mechanisms involved, remain disputed. Recent laboratory studies suggested that algae kill corals by inducing hypoxia on the coral surface, through stimulated microbial respiration. Methods/Findings: We examined the main premise of this hypothesis by measuring in situ oxygen microenvironments at the contact interface between the massive coral Porites spp. and turf algae, and between Porites spp. and crustose coralline algae (CCA). Oxygen levels at the interface were similar to healthy coral tissue and ranged between 300-400 μM during the day. At night, the interface was hypoxic (~70 μM) in coral-turf interactions and close to anoxic (~2 μM) in coral-CCA interactions, but these values were not significantly different from healthy tissue. The diffusive boundary layer (DBL) was about three times thicker at the interface than above healthy tissue, due to a depression in the local topography. A numerical model, developed to analyze the oxygen profiles above the irregular interface, revealed strongly reduced net photosynthesis and dark respiration rates at the coral-algal interface compared to unaffected tissue during the day and at night, respectively. Conclusions/Significance: Our results showed that hypoxia was not a consistent feature in the microenvironment of the coral-algal interface under in situ conditions. Therefore, hypoxia alone is unlikely to be the cause of coral mortality. Due to the modified topography, the interaction zone is distinguished by a thicker diffusive boundary layer, which limits the local metabolic activity and likely promotes accumulation of potentially harmful metabolic products (e.g., allelochemicals and protons). Our study highlights the importance of mass transfer phenomena and the need for direct in situ measurements of microenvironmental conditions in studies on coral stress. © 2012 Wangpraseurt et al

    Chemical and Physical Environmental Conditions Underneath Mat- and Canopy-Forming Macroalgae, and Their Effects on Understorey Corals

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    Disturbed coral reefs are often dominated by dense mat- or canopy-forming assemblages of macroalgae. This study investigated how such dense macroalgal assemblages change the chemical and physical microenvironment for understorey corals, and how the altered environmental conditions affect the physiological performance of corals. Field measurements were conducted on macroalgal-dominated inshore reefs in the Great Barrier Reef in quadrats with macroalgal biomass ranging from 235 to 1029 g DW m−2 dry weight. Underneath mat-forming assemblages, the mean concentration of dissolved oxygen was reduced by 26% and irradiance by 96% compared with conditions above the mat, while concentrations of dissolved organic carbon and soluble reactive phosphorous increased by 26% and 267%, respectively. The difference was significant but less pronounced under canopy-forming assemblages. Dissolved oxygen declined and dissolved inorganic carbon and alkalinity increased with increasing algal biomass underneath mat-forming but not under canopy-forming assemblages. The responses of corals to conditions similar to those found underneath algal assemblages were investigated in an aquarium experiment. Coral nubbins of the species Acropora millepora showed reduced photosynthetic yields and increased RNA/DNA ratios when exposed to conditions simulating those underneath assemblages (pre-incubating seawater with macroalgae, and shading). The magnitude of these stress responses increased with increasing proportion of pre-incubated algal water. Our study shows that mat-forming and, to a lesser extent, canopy-forming macroalgal assemblages alter the physical and chemical microenvironment sufficiently to directly and detrimentally affect the metabolism of corals, potentially impeding reef recovery from algal to coral-dominated states after disturbance. Macroalgal dominance on coral reefs therefore simultaneously represents a consequence and cause of coral reef degradation

    Crustose coralline algae can contribute more than corals to coral reef carbonate production

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    This is the final version. Available on open access from Nature Research via the DOI in this recordData availability: Data are available at https://github.com/JayCrlt/CCA_MethodsCode availability: Codes are available at https://github.com/JayCrlt/CCA_MethodsUnderstanding the drivers of net coral reef calcium carbonate production is increasingly important as ocean warming, acidification, and other anthropogenic stressors threaten the maintenance of coral reef structures and the services these ecosystems provide. Despite intense research effort on coral reef calcium carbonate production, the inclusion of a key reef forming/accreting calcifying group, the crustose coralline algae, remains challenging both from a theoretical and practical standpoint. While corals are typically the primary reef builders of contemporary reefs, crustose coralline algae can contribute equally. Here, we combine several sets of data with numerical and theoretical modelling to demonstrate that crustose coralline algae carbonate production can match or even exceed the contribution of corals to reef carbonate production. Despite their importance, crustose coralline algae are often inaccurately recorded in benthic surveys or even entirely missing from coral reef carbonate budgets. We outline several recommendations to improve the inclusion of crustose coralline algae into such carbonate budgets under the ongoing climate crisis.French Embassy - French Related Research Projects (F2RP)Agence Nationale de la Recherche (ANR)Royal Society of New Zealand Te Apārang

    Doom and Boom on a Resilient Reef: Climate Change, Algal Overgrowth and Coral Recovery

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    Background: Coral reefs around the world are experiencing large-scale degradation, largely due to global climate change, overfishing, diseases and eutrophication. Climate change models suggest increasing frequency and severity of warming-induced coral bleaching events, with consequent increases in coral mortality and algal overgrowth. Critically, the recovery of damaged reefs will depend on the reversibility of seaweed blooms, generally considered to depend on grazing of the seaweed, and replenishment of corals by larvae that successfully recruit to damaged reefs. These processes usually take years to decades to bring a reef back to coral dominance
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