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11.
Diane Lefebvre Jacqueline Pierre Yannick Outreman Jean-Sébastien Pierre 《Behavioral ecology and sociobiology》2007,61(11):1707-1715
The patch living rules of a pollinator, the bumblebee Bombus terrestris L., are studied here in the framework of motivational models widely used for parasitoids: The rewarding events found during
the foraging process are supposed to increase or decrease suddenly the tendency of the insect to stay in the current patch
and therefore to adjust the patch residence time to the patch profitability. The foraging behaviour of these pollinators was
observed in two environment types to determine their patch-leaving decisions. The rich environment was composed of male-fertile
flowers, offering pollen and nectar, and the poor one of male-sterile flowers, offering little nectar and no pollen. The experimental
design consisted of a patch system in which inflorescences were evenly arranged in two rows (1 m distance). Residence times
of foragers inside inflorescences and rows were analysed by a Cox proportional hazards model, taking into account recent and
past experience acquired during the foraging bout. Most of the results showed a decremental motivational mechanism, that is,
a reduction in the residence time on the inflorescence or in the row related to exploitation of flowers within inflorescences
and inflorescences within rows These results indicate that bumblebees tend to leave the patch using departure rules similar
to those found in parasitoids. The results also provide information on the memory, learning and evaluating capabilities of
bumblebees especially when rich and poor environments were compared. The patch-leaving mechanism suggested by this study is
consistent with the central place foraging theory. 相似文献
12.
Dargie Greta C. Lawson Ian T. Rayden Tim J. Miles Lera Mitchard Edward T. A. Page Susan E. Bocko Yannick E. Ifo Suspense A. Lewis Simon L. 《Mitigation and Adaptation Strategies for Global Change》2019,24(4):669-686
Mitigation and Adaptation Strategies for Global Change - The recent publication of the first spatially explicit map of peatlands in the Cuvette Centrale, central Congo Basin, reveals it to be the... 相似文献
13.
Mamindy-Pajany Y Hamer B Roméo M Géret F Galgani F Durmiši E Hurel C Marmier N 《Chemosphere》2011,82(3):362-369
This work investigates the ecotoxicological evaluation of contaminated dredged sediments from French Mediterranean navy harbour (A), commercial port (B) and two composite specimens (C) and (D) coming from the mixture of A and B with other port sediments. The toxicity of elutriates from these sediments is estimated using embryo-toxicity test, Microtox® solid phase test, LuminoTox, phytotoxicity tests and genotoxicity test. Bioassay responses are not clearly correlated with chemical contamination in the whole sediment and vary as a function of tested organisms. The highest contaminated samples (A and C) are almost always more toxic than the less contaminated samples (B and D). Among composite sediments, the mixture effect with other sediments is not efficient to decrease toxicity in sample C, suggesting that other parameters influence toxicity level such as particle size or organic matter content. These parameters should be taken into consideration in order to improve the efficiency of the mixture process and produce composite sediments with low toxicity. 相似文献
14.
Yannick Mamindy-Pajany Stéphanie Sayen Emmanuel Guillon 《Environmental science and pollution research international》2013,20(7):4414-4423
A soil column adsorption–desorption study was performed on an agricultural calcareous soil to determine the impact of sewage sludge spreading on nickel mobility. Ni adsorption experiments were followed by desorption tests involving the following liquid extractants: water, calcium (100 mg/L), oxalic acid (525 mg/L equivalent to 100 mg carbon/L), and sludge extracts (0.5 and 2.5 g/L). Desorption tests were also conducted after sewage sludge spreading at three application rates (30, 75, and 150 t/ha). According to the breakthrough curve, Ni adsorption was irreversible and occurred mainly through interactions with calcite surface sites. Nickel desorption from the soil column was promoted in presence of significant dissolved organic carbon (DOC) concentration as observed with oxalic acid elution and sludge extract at 2.5 g/L. In sludge-amended soil columns, the maximum Ni levels occurred in first pore volumes, and they were positively correlated to the sludge application rate. The presence of DOC in leaching waters was the main factor controlling Ni desorption from the sludge-amended soil columns. This finding implies that DOC generated by sludge applied on calcareous soils might facilitate the leaching of Ni due to the formation of soluble Ni–organic complexes. Thus, sludge application can have potential environmental impacts in calcareous soils, since it promotes nickel transport by decreasing Ni retention by soil components. 相似文献
15.
Batch and column studies of the stabilization of toxic heavy metals in dredged marine sediments by hematite after bioremediation 总被引:1,自引:0,他引:1
Yannick Mamindy-Pajany Florence Geret Charlotte Hurel Nicolas Marmier 《Environmental science and pollution research international》2013,20(8):5212-5219
The management of dredged sediments is an important issue in coastal regions where the marine sediments are highly polluted by metals and organic pollutants. In this paper, mineral-based amendments (hematite, zero-valent iron and zeolite) were used to stabilize metallic pollutants (As, Cd, Cu, Mo, Ni, Pb, and Zn) in a contaminated marine sediment sample. Mineral-based amendments were tested at three application rates (5 %, 10 %, and 15 %) in batch experiments in order to select the best amendment to perform column experiments. Batch tests have shown that hematite was the most efficient amendment to stabilize inorganic pollutants (As, Cd, Cu, Mo, Ni, Pb, and Zn) in the studied sediment. Based on batch tests, hematite was used at one application rate equal to 5 % to conduct column experiments. Column tests confirmed that hematite was able to decrease metal concentrations in leachates from stabilized sediment. The stabilization rates were particularly high for Cd (67 %), Mo (80 %), and Pb (90 %). The Microtox solid phase test showed that hematite could decrease significantly the toxicity of stabilized sediment. Based on batch and column experiments, it emerged that hematite could be a suitable adsorbent to stabilize metals in dredged marine sediment. 相似文献
16.
17.
Yannick Outreman Anne Le Ralec Eric Wajnberg Jean-Sébastien Pierre 《Behavioral ecology and sociobiology》2005,58(2):208-217
The present study aimed to address how an insect parasitoid makes patch-departure decisions from various types of host patches and how previous patch experiences in the environment modify this decision-making process. Experiments were done with the parasitic wasp Aphidius rhopalosiphi attacking the grain aphid Sitobion avenae. In the experiments, wasps were observed in a laboratory environment containing several patches of various host densities, and behavioural records were analysed using a Coxs proportional hazards model. Consideration of the effect of the within-patch experience gave a classic pattern of patch-leaving decision rules in parasitoids: A. rhopalosiphi used local information on host quality (i.e. numbers of ovipositions or rejections) and availability (i.e. patch density) to determine departure decision. However, consideration of previous patch experiences provided evidence that these departure rules are fundamentally dynamic, responding to the physiological state of the animal and the information it has about its environment. Results showed that A. rhopalosiphi decreased its tendency to leave the visited patch after an oviposition. However, when a female has already laid several other eggs in the environment, such an incremental mechanism gradually switched to a decremental one. Hence, A. rhopalosiphi responded to egg-load depletion by leaving the visited patches sooner and by depositing a smaller number of eggs in those patches, which probably led to a decreased level of superparasitism. Results also indicated that previous experiences enabled wasps to estimate spatial host distribution and then to adjust their behavioural decisions accordingly. Thus, A. rhopalosiphi was shown to adjust its patch residence time according to the quality and the number of the patches previously visited. These proximate mechanistic rules adopted by A. rhopalosiphi females are discussed in the context of general predictions from optimality models.Communicated by D. Gwynne 相似文献
18.
Michel Schalk Marie-Agnès Pierrel Alfred Zimmerlin Yannick Batard Francis Durst Danièle Werck-Reichhart 《Environmental science and pollution research international》1997,4(4):229-234
The ability of a plant cytochrome P450 to bind and metabolise plant endogenous molecules and xenobiotics was investigated.
The work was performed on the yeast-expressed CYP73A1, a cinnamate 4-hydroxylase isolated fromHelianthus tuberosus. CYP73 controls the general phenylpropanoid pathway and is likely to be one of the most abundant sources of P450 in the biosphere.
The enzyme shows a high selectivity toward plant secondary metabolites. Nevertheless, it oxygenates several small and planar
xenobiotics with low efficiency, including an herbicide (chlorotoluron). One xenobiotic molecule, 2naphthoic acid, is hydroxylated
with an efficiency comparable to that of the physiological substrate. This reaction was used to devise a fluorimetric test
for the rapid measurement of enzyme activity. A series of herbicidal molecules (hydroxybenzonitriles) are shown to bind the
active site without being metabolised. These molecules behave as strong competitive inhibitors of CYP73 with a Ki in the same micromolar range as the Km for the physiological substrate. It is proposed that their inhibition of the phenylpropanoid pathway reinforces their other
phytotoxic effects at the level of the chloroplasts. All our results indicate a strong reciprocal interaction between plant
P450s and xenobiotics. 相似文献
19.
Yannick Beauregard Juliana Ramsay Bruce Ramsay 《Journal of Polymers and the Environment》2016,24(3):281-285
Although poly-3-hydroxyalkanoates (PHAs) and particularily medium-chain-length (mcl)-PHAs are likely to find industrial applications in a latex form, very few studies have examined their behavior in aqueous suspension and none have examined the dense suspensions required commercially. For this reason, the stability of mcl-PHA latexes containing saturated aliphatic (65 mol% 3-hydroxynonanoate, PHN), and for the first time, with vinyl (PHNU) or carboxylated side chains was examined. At 4 g L?1 with no stabilizing agent, PHNU nanoparticles (199.4 ± 3.6 nm) were significantly smaller than those of PHN (211.5 ± 6.4 nm) while carboxylated PHN nanoparticles (76.1 ± 6.4 nm) were substantially smaller than those of either PHN or PHNU with particles stable for more than 110 days. Increasing the PHN concentration to 10 g L?1 also resulted in stable latexes but with larger particles (410.8 ± 5.2 nm). Adjusting the pH of the suspending medium (water) before addition of the polymer (dissolved in acetone) resulted in much smaller PHN particles at pH = 11.3 (134 ± 2 nm) than at pH = 4.3 (312 ± 8 nm) at a 4 g L?1 final polymer concentration. Zeta potentials of PHN suspensions decreased with pH, likely due to the carboxyl end groups. Above a pH of 4.0, adjusting the pH after particle formation had little effect. NaCl addition could be used to agglomerate and ultimately precipitate the particles. Stabilizers such as surfactants will likely be required to produce denser mcl-PHA latexes with suitable particle size for certain applications such as coatings and toner production. 相似文献
20.
Test procedure for evaluating the human–machine interface of vehicles with automated driving systems
Frederik Naujoks Sebastian Hergeth Katharina Wiedemann Nadja Schömig Yannick Forster Andreas Keinath 《Traffic injury prevention》2019,20(4):S146-S151
AbstractObjective: The human–machine interface (HMI) is a crucial part of every automated driving system (ADS). In the near future, it is likely that—depending on the operational design domain (ODD)—different levels of automation will be available within the same vehicle. The capabilities of a given automation level as well as the operator’s responsibilities must be communicated in an appropriate way. To date, however, there are no agreed-upon evaluation methods that can be used by human factors practitioners as well as researchers to test this.Methods: We developed an iterative test procedure that can be applied during the product development cycle of ADS. The test procedure is specifically designed to evaluate whether minimum requirements as proposed in NHTSA’s automated vehicle policy are met.Results: The proposed evaluation protocol includes (a) a method to identify relevant use cases for testing on the basis of all theoretically possible steady states and mode transitions of a given ADS; (b) an expert-based heuristic assessment to evaluate whether the HMI complies with applicable norms, standards, and best practices; and (c) an empirical evaluation of ADS HMIs using a standardized design for user studies and performance metrics.Conclusions: Each can be used as a stand-alone method or in combination to generate objective, reliable, and valid evaluations of HMIs, focusing on whether they meet minimum requirements. However, we also emphasize that other evaluation aspects such as controllability, misuse, and acceptance are not within the scope of the evaluation protocol. 相似文献