bluuebunny/crossref_metadata_2025 huggingface dataset:
Methods for assessing risk from climate hazards in urban areas
Authors: Gwilliam J. , Fedeski M. , Lindley S. , Theuray N. , Handley J.
Published: December 2006

This paper describes methodologies for assessing risk at conurbation and neighbourhood scales that have been developed in order to provide urban planners with a toolkit for the assessment of risk due to climatic hazards. The methodologies treat risk as a function of hazard, vulnerability and exposure, all three of which elements are influenced by climate change. These three elements are represented as geospatial data layers in a geographical information system (GIS), in order to provide a logical framework to assist planning and management for communities that are safer, more sustainable and more resilient in the face of climate change. The risk assessment methodologies have initially been developed and applied at two different scales: a conurbation scale, using a screening process to locate areas of high risk to assist with land use planning tasks, and a neighbourhood scale, focusing on the influence of the vulnerability of the building stock on this risk. However, using the two methodologies in tandem can refine the assessment further, so the potential development and application of a combined methodology is explored.
Cellular physiological effects of the MV Kyowa violet fuel-oil spill on the hard coral, Porites lobata
Authors: Downs Craig A. , Richmond Robert H. , Mendiola Woon Jaye , Rougée Luc , Ostrander Gary K.
Published: December 2006

The grounding of the Merchant Vessel (MV) Kyowa Violet on a coral reef near Yap, Federated States of Micronesia, in December 2002 resulted in the release of an estimated 55,000 to 80,000 gallons of intermediate fuel oil grade 180. The immediate impact was the widespread coating of mangroves and the intertidal zone along more than 8 km of coastline. Of greater concern, however, was the partitioning of the fuel oil in the water column, leading to chronic exposure of organisms in the ecosystem for a considerable period after the initial event. Herein, we report on our examination of one coral species, Porites lobata, nearly three months after the initial exposure. We investigated whether changes in cellular physiology were consistent with the pathological profile that results from the interaction of corals with polycyclic aromatic hydrocarbons, the principal constituent of fuel oil. Specifically, we document, to our knowledge for the first time, changes in the cellular physiological condition of an exposed coral population affected by a fuel-oil spill. We also provide evidence that the observed changes are consistent with a recent exposure to fuel oil, as evidenced by the presence of characteristic cellular lesions attributed to polycyclic aromatic hydrocarbons. Finally, our data support a model for a mechanistic relationship between the cellular pathological profile of the coral and a recent petroleum exposure, such as the MV Kyowa Violet fuel oil spill.
Toxicity of six pesticides to common frog (Rana temporaria) tadpoles
Authors: Johansson Markus , Piha Henna , Kylin Henrik , Merilä Juha
Published: December 2006

Amphibian species inhabiting agricultural areas may be exposed to pesticides during their aquatic larval phase. We tested the toxicity of six commonly used pesticides on Rana temporaria spawn and tadpoles. In acute tests, tadpoles were exposed to relatively high concentrations of azoxystrobin, cyanazine, esfenvalerate, MCPA ([4-chloro-2-methylphenoxy] acetic acid), permethrin, and pirimicarb for 72 h. Chronic exposure tests were performed from fertilization to metamorphosis with azoxystrobin, cyanazine, and permethrin at concentrations similar to those found in surface waters in agricultural areas in Sweden. The most lethal pesticides in the acute exposure were azoxystrobin, permethrin, and pirimicarb. Also, negative effects on the growth of the tadpoles were observed with azoxystrobin, cyanazine, and permethrin. The chronic exposure at lower pesticide concentrations did not result in increased mortality or impaired growth. However, we found a positive effect of permethrin on growth and size at metamorphosis. The results suggest that the examined pesticides can inflict strong negative effects at high concentrations but have no or relatively weak effects on R. temporaria spawn or tadpoles at concentrations found in Swedish surface waters.
Utility of in vitro test methods to assess the activity of xenoestrogens in fish
Authors: Marlatt Vicki L. , Hewitt L. Mark , Van Der Kraak Glen
Published: December 2006

The results of the present study have demonstrated the utility of an estrogen receptor (ER) competitive ligand-binding assay, a hepatocyte vitellogenin (VTG) induction bioassay, and an ER reporter gene bioassay in characterizing the activity of model estrogen agonists (17β-estradiol [E2], ethynylestradiol, and nonylphenol) and antagonists (tamoxifen and ZM 189154) in rainbow trout (Oncorhynchus mykiss). The in vitro results were validated against in vivo trout waterborne exposures to E2 and tamoxifen. The results showed that all three in vitro assays were capable of detecting the hormonal activities of the selected model compounds in a dose-dependent manner, with the exception of nonylphenol in the ER reporter gene bioassay. However, the relative potency rankings of the model compounds were not consistent between these assays, which suggests that the relative potencies obtained within assays may have limited predictive value between assays. Discrepancies in potencies most likely can be attributed to the different levels of cellular organization in each assay. In addition to model compounds, we also evaluated the responses of the ER-binding assay and the hepatocyte VTG induction bioassay to complex mixtures associated with endocrine effects in fish, specifically extracts of pulp mill effluent. Of the 14 pulp mill effluent extracts tested, only six showed activity in both assays, whereas the remaining eight samples showed activity in only one of the two assays. The hepatocyte VTG induction bioassay consistently showed that the pulp mill effluent extracts were antiestrogenic, which to our knowledge has not been reported in previous studies. Collectively, these results suggest that a combination of in vitro assays that depend on differing endpoints is required to identify potential xenoestrogens and to characterize their modes of action.
Time dependence of phase distribution of pyrethroid insecticides in sediment
Authors: Bondarenko Svetlana , Putt Arthur , Kavanaugh Stacy , Poletika Nick , Gan Jianying
Published: December 2006

Synthetic pyrethroids are strongly hydrophobic compounds, and their toxicity in sediment is regulated by phase distribution among the sediment, dissolved organic matter, and water phases. In the present study, we spiked and equilibrated four pyrethroids in two sediments, and we characterized their phase distribution as a function of contact time. The freely dissolved concentration measured by solid-phase microextraction was only a small fraction (<16.3%) of the total pore-water concentration as determined by liquid–liquid extraction. The fraction of the freely dissolved concentration was significantly greater in the freshwater sediment (1.7–16.3%) than in the marine sediment (1.1–4.2%) following 9 d of equilibration, and it decreased substantially with contact time to less than 5% at 30 d after sediment dosing. Consequently, the apparent organic carbon partition coefficient (KOC) and dissolved organic carbon partition coefficient (KDOC) values increased significantly over the contact time, especially in the freshwater sediment, suggesting that phase distribution was not at equilibrium after 9 d of equilibration. If only the freely dissolved concentration is bioavailable, these observations suggest that contact time after sediment dosing may greatly affect the bioavailability and, hence, the toxicity of pyrethroids. Therefore, a long contact time (≥30 d) is recommended for sediment toxicity testing of this class of compounds. The dependence of bioavailability on contact time also implies that test conditions must be standardized to allow comparison between laboratory-dosed samples and field samples.
Toxicity of four veterinary parasiticides on larvae of the dung beetle Aphodius constans in the laboratory
Authors: Hempel Hella , Scheffczyk Adam , Schallnaß Hans-Joachim , Lumaret Jean-Pierre , Alvinerie Michel , Römbke Jörg
Published: December 2006

The environmental risk assessment of veterinary pharmaceuticals for dung beetles is strongly hampered because no standardized test method is available so far. Therefore, a test with the temperate dung beetle species Aphodius constans was developed. The survival of beetle larvae was determined after exposure to four veterinary parasitical pharmaceuticals (ivermectin, moxidectin, dicyclanil, and praziquantel) representing different treatment regimes, modes of action, and effect levels. The test was performed in the laboratory (three week duration) with fresh dung, as well as formulated (dried, ground, and rewetted) dung as test substrate (i.e., at least one range-finding test, two definitive test runs per pharmaceutical). Ivermectin was the most toxic substance (median lethal concentration [LC50] = 0.88–0.98 mg of active substance per kilogram of dung dry weight [mg a.s./kg dung (dry wt)] followed by dicyclanil (LC50 = 1.5–6.0 mg a.s./kg dung [dry wt]) and moxidectin (LC50 = 4.0–5.4 mg a.s./kg dung [dry wt]), whereas praziquantel showed very low toxicity (LC50 > 1,000 mg a.s./kg dung [dry wt]). The toxicity in fresh and formulated dung differed by a factor of between 1.1 and 4. The comparison with literature data on toxic effects of these substances on dung beetles in the laboratory or in the field is difficult because no results for praziquantel and dicyclanil have been published so far. With the use of data from ivermectin and moxidectin, the test results are on the same order of magnitude as those known from other studies. On the basis of the experiments reported here, it is recommended that this test be standardized in an international ring test so that it can be incorporated into the risk assessment process as described in the respective international guidelines for the registration of veterinary pharmaceuticals.
Chemical and biological pollution contribute to the immunological profiles of free-ranging harbor seals
Authors: Mos Lizzy , Morsey Brenda , Jeffries Steven J. , Yunker Mark B. , Raverty Stephen , Guise Sylvain De , Ross Peter S.
Published: December 2006

Polychlorinated biphenyls and other persistent organic pollutants have been associated with immunotoxicity and outbreaks of (infectious) disease in marine mammals by rendering them vulnerable to infection by pathogens such as viruses and bacteria. In an immunotoxicological study of free-ranging harbor seals (Phoca vitulina), we obtained samples of blood and blubber from seal pups that were live-captured from two remote and two near-urban sites in British Columbia, Canada, and Washington state, USA. Using these samples, we quantified hematology, innate immune function, adaptive immune function, and polychlorinated biphenyl accumulation. While controlling for confounding factors (age, sex, and condition), univariate correlations between phagocytosis (r2 = 0.30, p = 0.002), respiratory burst (r2 = 0.45, p = 0.000), T-lymphocyte function (r2 = 0.16, p = 0.028), lymphocyte signaling (r2 = 0.17, p = 0.025), and lymphocyte counts (r2 = 0.29, p = 0.002), and polychlorinated biphenyl concentrations suggested chemical-associated immunotoxicity. Principal component analysis of immunological endpoints provided additional evidence of immunotoxic effects in seals. However, principal component analysis also identified a noncontaminant-related factor by distinguishing between seals inhabiting urban versus remote sites, with results being consistent with increased pathogen exposure. Elevated fecal coliform concentrations in water, and observations of terrestrial spill-over pathogens in local seals, further support the notion of biological pollution at these sites. Although our study highlights the role that environmental contaminants might play in rendering marine mammal populations vulnerable to disease through immunotoxicity, it also suggests that biological pollution represents an emerging conservation concern.
Toxicity and bioaccumulation of 2, 4, 6-trinitrotoluene in fathead minnow (Pimephales promelas)
Authors: Yoo Leslie J. , Lotufo Guilherme R. , Gibson Alfreda B. , Steevens Jeffery A. , Sims Jerre G.
Published: December 2006

Few studies have determined the toxicity and bioaccumulation potential of explosive compounds in freshwater fish. In the present study, fathead minnow (Pimephales promelas) were exposed to a range of 2, 4, 6-trinitrotoluene (TNT) concentrations (0.44–44 μmol/L [0.1–10 mg/L] and 4.4–22.0 μmol/L [1.0–5.0 mg/L] in 4- and 10-d experiments, respectively). Median lethal concentrations of 11.93 μmol/L (2.7 mg/L; 95% confidence limit [CL], 10.29–13.83 μmol/L) and 9.68 μmol/L (2.20 mg/L; 95% CL, 9.17–10.22 μmol/L) were calculated in the 4- and 10-d experiments, respectively, and median lethal body residue of 101.0 μmol/kg (95% CL, 86.0–118.7 μmol/kg) was calculated in 4-d experiments. To study bioaccumulation, fish were exposed to 4.4 μmol/L (1 mg/L) of TNT for 12 h. Rapid bioaccumulation of TNT occurred within the first 10 min of exposure (ku = 30.4 L/kg/h). Elimination of ΣTNT (molar sum of TNT and degradation products 2- and 4-aminodinitrotoluenes) was fast, with an elimination rate (ke) of 2.24/h and a short half-life (0.31 h). The bioconcentration factors determined using 6-h mean tissue and water concentrations of ΣTNT were 8.40 and 4.68 L/kg for the uptake experiment and the uptake portion of the elimination experiments, respectively. To determine the target organ for TNT in fish, juvenile fathead minnow were exposed to 2.2 μmol/L (0.5 mg/L) of [14C]TNT for 10 d. Radiolabeled compounds primarily bioaccumulated in the visceral tissues and spleen in comparison to gill, brain, muscle, and remainder tissue groups. The present study demonstrates the low bioaccumulation potential and rapid uptake of TNT in the fathead minnow.
In vitro degradation of hexanitrohexaazaisowurtzitane (CL-20) by cytosolic enzymes of Japanese quail and the rabbit
Authors: Bardai Ghalib K. , Halasz Annamaria , Sunahara Geoffrey I. , Dodard Sabine , Spear Philip A. , Grosse Stephan , Hoang Johnston , Hawari Jalal
Published: December 2006

Hexanitrohexaazaisowurtzitane (CL-20) is a polycyclic nitramine explosive and propellant, currently being considered as a potential replacement for existing cyclic nitramine explosives. Earlier studies have provided evidence suggestive of adverse liver effects in adult Coturnix spp. exposed to CL-20, yet analysis of tissue samples (plasma, liver, brain, heart, or spleen) indicated that CL-20 was not detectable in these treated animals. The present study was conducted to identify and purify the enzymes capable of CL-20 biotransformation. Results indicate that the hepatic biotransformation of CL-20 in vitro was inhibited by ethacrynic acid (93%) and by the glutathione (GSH) analogue S-octylglutathione (80%), suggesting the involvement of glutathione-S-transferase (GST). Partially purified cytosolic α- and μ-type GST (requiring presence of GSH as a cofactor) from quail and rabbit liver was capable of CL-20 biotransformation. The degradation of CL-20 (0.30 ± 0.05 and 0.40 ± 0.02 nmol/min/mg protein for quail and rabbit, respectively) was accompanied with the formation of nitrite and consumption of GSH. Using liquid chromatography/mass spectrometry, we detected two intermediates, that is, open-ring, monodenitrated GSH–conjugated CL-20 biotransformation product with the same deprotonated molecular mass ion at 699 Da, suggesting isomeric forms of the intermediate metabolites. Identity of the conjugated metabolites was confirmed by using ring-labeled [15N]CL-20 and the nitro group–labeled [15NO2]CL-20. These data suggest that the in vitro biotransformation of CL-20 by GST under the conditions tested may be a key initial step in the in vivo degradation of CL-20 in the quail and resulted in the formation of more biologically reactive intermediates than the parent compound. These data will aid in our understanding of the biotransformation processes of CL-20 in vivo.
Physiological modes of action of toxic chemicals in the nematodeAcrobeloides nanus
Authors: Álvarez Olga Alda , Jager Tjalling , Redondo Eliana Marco , Kammenga Jan E.
Published: December 2006

To gain a better understanding of the mechanisms through which a chemical exerts toxicity, a deeper insight is needed regarding the physiological processes that take place during a toxic stress. This issue can have important benefits for risk assessment, because it can contribute to a better interpretation of toxicity data. Here, we study the physiological mode of action of three different compounds (cadmium, carbendazim, and pentachlorobenzene) with an experimental data–based approach using whole life-cycle toxicity data from the nematode Acrobeloides nanus. We use a process–based model, based on the dynamic energy budget theory, to study the fluxes of energy related to physiological processes and their variation throughout the life cycle. With this approach, we unravel the physiological modes of action based on resource allocation, and we model the effects of the different modes of action at the population level. The mode of action of carbendazim was through a decrease in assimilation, with an additional effect on the production of reactive oxygen species (ROS). Cadmium increased the costs of growth, with an extra effect on ROS production, and pentachlorobenzene decreased assimilation. We compared the present results with those of previous studies using the nematode Caenorhabditis elegans, and we found that the modes of action for the three compounds differed from those found in A. nanus, showing that the life-history characteristics of each organism have a clear influence on the resulting modes of action. This highlights the importance of the interactions between a chemical and the biological characteristics of the organism in determination of the resulting physiological modes of action.
Volatile organic sulfur compounds in anaerobic sludge and sediments: Biodegradation and toxicity
Authors: van Leerdam Robin C. , de Bok Frank A. M. , Lomans Bart P. , Stams Alfons J. M. , Lens Piet N. L. , Janssen Albert J. H.
Published: December 2006

A variety of environmental samples was screened for anaerobic degradation of methanethiol, ethanethiol, propanethiol, dimethylsulfide, and dimethyldisulfide. All sludge and sediment samples degraded methanethiol, dimethylsulfide, and dimethyldisulfide anaerobically. In contrast, ethanethiol and propanethiol were not degraded by the samples investigated under any of the conditions tested. Methanethiol, dimethylsulfide, and dimethyldisulfide were mainly degraded by methanogenic archaea. In the presence of sulfate and the methanogenic inhibitor bromoethane sulfonate, degradation of these compounds coupled to sulfate reduction occurred as well, but at much lower rates. Besides their biodegradability, also the toxicity of methanethiol, ethanethiol, and propanethiol to methanogenesis with methanol, acetate, and H2/CO2 as the substrates was assessed. The 50% inhibition concentration of methanethiol on the methane production from these substrates ranged between 7 and 10 mM. The 50% inhibition concentration values of ethanethiol and propanethiol for the degradation of methanol and acetate were between 6 and 8 mM, whereas hydrogen consumers were less affected by ethanethiol and propanethiol, as indicated by their higher 50% inhibition concentration (14 mM). Sulfide inhibited methanethiol degradation already at relatively low concentrations: methanethioldegradation was almost completely inhibited at an initial sulfide concentration of 8 mM. These results define the operational limits of anaerobic technologies for the treatment of volatile organic sulfur compounds in sulfide-containing wastewater streams.
Assimilation of cadmium in a European lacertid lizard: Is trophic transfer important?
Authors: Mann Reinier M. , Serra Elisabete A. , Soares Amadeu M. V. M.
Published: December 2006

Apart from analyses for elemental contaminants in field-collected specimens, very little is known about the assimilation and accumulation of inorganic contaminants in reptiles. Recent dietary studies with reptiles (and some other vertebrates and invertebrates) have taken care to incorporate the principles of trophic transfer by pre-exposing prey items to the elemental contaminant of interest. However, there are conflicting data in the literature as to whether biologically incorporated metals are more bioavailable to consumers in a food chain than simple salts added to the diet, and this study examines this issue in a lacertid lizard. Adult individuals of Podarcis carbonelli were exposed to cadmium (Cd) in a 21-week dietary study to determine whether the form in which the Cd is provided influences assimilation efficiency for this metal. Lizards were provided with Cd that had either been biologically incorporated into crickets or as Cd(NO3)2 added superficially to crickets just prior to feeding. Radiospectrometric analysis for 109Cd in animal tissues and fecal material was used to follow Cd accumulation over the duration of exposure. The highest levels of accumulation were found within the gut. This, combined with the observation of higher rates of assimilation over the first five weeks, strongly suggests a rapid accumulation of Cd within the gut tissue followed by a slower redistribution to other tissues. No statistically different levels of Cd assimilation efficiency were detected between the two treatment groups, nor were there any statistically significant differences between the two treatment groups in relation to the proportional distribution to the gut, liver, or kidneys.
Toxic effects and oxidative stress in higher plants exposed to polycyclic aromatic hydrocarbons and their N-heterocyclic derivatives
Authors: Pašková Veronika , Hilscherová Klára , Feldmannová Marie , Bláha Luděk
Published: December 2006

N-heterocyclic derivatives of polycyclic aromatic hydrocarbons (NPAHs) are widespread concomitantly with their parent analogues and have been detected in air, water, sediments, and soil. Although they were shown to be highly toxic to some organisms, our understanding of their occurrence, environmental fate, biological metabolism, and effects is limited. This study evaluated toxic effects of three homocyclic aromatic hydrocarbons (PAHs—phenanthrene, anthracene, fluorene) and their seven N-heterocyclic derivates on higher terrestrial plants Sinapis alba, Triticum aestivum, and Phaseolus vulgaris. Germinability, morphological end-points, parameters of detoxification, and antioxidant components of plant metabolism as well as lipid peroxidation were studied in acute phytotoxicity tests. Phytotoxicity of NPAHs was generally more pronounced than the effects of parent PAHs, and it significantly differed with respect to the structure of individual NPAHs. Sinapis alba and T. aestivum were more sensitive plant species than P. vulgaris. Chemicals with the strongest inhibition effect on germination and growth of plants were phenanthridine, acridine, benzo[h]quinoline, and 1,10- and 1,7-phenanthroline. All tested chemicals significantly induced activities of detoxification and antioxidant enzymes (glutathione reductase, glutathione peroxidase, and glutathione-S-transferase) at nanomolar to low micromolar concentrations. Levels of reduced glutathione were induced by all tested chemicals except 1,10- and 4,7-phenanthroline. Furthermore, fluorene, carbazole, acridine, phenanthrene, phenanthridine, benzo[h]quinoline, and 1,7-phenanthroline significantly increased lipid peroxidation. The results of our study newly demonstrate significant toxicity of NPAHs to plants and demonstrate suitability of multiple biomarker assessment to characterize mechanisms of oxidative stress and to serve as an early warning of phytotoxicity in vivo.
Arsenate sorption on two chinese red soils evaluated with macroscopic measurements and extended X-ray absorption fine-structure spectroscopy
Authors: Luo Lei , Zhang Shuzhen , Shan Xiao-Quan , Jiang Wei , Zhu Yong-Guan , Liu Tao , Xie Ya-Ning , McLaren Ronald G.
Published: December 2006

Arsenic sorption is the primary factor that affects the bioavailability and mobility of arsenic in soils. To elucidate the characteristics and mechanisms of arsenate, As(V), sorption on soils, a combination of sorption isotherms, zeta potential measurements, and extended X-ray absorption fine-structure (EXAFS) spectroscopy was used to investigate As(V) sorption on two Chinese red soils. Arsenate sorption increased with increasing As(V) concentration and was insensitive to ionic strength changes at pH 6.0. Arsenate, mainly as H2AsO4– in soil solution at pH 6.0, was strongly sorbed mainly through ligand exchange by the two soils. The sorption capacity was affected by the iron and aluminum mineral contents in the soils. The zeta potential measurements showed that As(V) sorption lowered the zeta potential and the points of zero charge of the soils. The EXAFS data indicate that adsorbed As(V) forms inner-sphere complexes with bidentate–binuclear configurations, as evidenced by an As–Fe bond distance of 3.28 ± 0.04 Å and an As–Al bond distance of 3.17 ± 0.03 Å. The two As(V) complexes were stable at different As(V) loadings, whereas the proportions were related to the aluminum and iron mineral contents in the soils. This study illuminated the importance of inclusion of microscopic and macroscopic experiments to elucidate sorption behavior and mechanisms.
Examining multiple sublethal contaminants on the gray treefrog (Hyla versicolor): Effects of an insecticide, herbicide, and fertilizer
Authors: Boone Michelle D. , Bridges-Britton Christine M.
Published: December 2006

We examined the single and interactive effects of an insecticide, an herbicide, and a fertilizer on gray treefrog (Hyla versicolor) tadpoles. Tadpoles were reared in mesocosms from hatching through metamorphosis and were exposed to the presence or absence of as many as three contaminants. Tadpoles did not appear to be more susceptible to single versus multiple contaminants, which may result from positive changes in food resources that compensate for the effects of other contaminants.
HOW RESEARCH IN BEHAVIORAL PHARMACOLOGY INFORMS BEHAVIORAL SCIENCE
Authors: Branch Marc N.
Published: December 2006

Behavioral pharmacology is a maturing science that has made significant contributions to the study of drug effects on behavior, especially in the domain of drug‐behavior interactions. Less appreciated is that research in behavioral pharmacology can have, and has had, implications for the experimental analysis of behavior, especially its conceptualizations and theory. In this article, I outline three general strategies in behavioral pharmacology research that have been employed to increase understanding of behavioral processes. Examples are provided of the general characteristics of the strategies and of implications of previous research for behavior theory. Behavior analysis will advance as its theories are challenged.
FUNCTION TRANSFORMATION WITHOUT REINFORCEMENT
Authors: Tonneau François , Arreola Fara , Martínez Alma Gabriela
Published: December 2006

In studies of function transformation, participants initially are taught to match stimuli in the presence of a contextual cue, X; the stimuli to be matched bear some formal relation to each other, for example, a relation of opposition or difference. In a second phase, the participants are taught to match arbitrary stimuli (say, A and B) in the presence of X. In a final test, A often displays behavioral functions that differ from those of B, and can be predicted from the nature of the relation associated with X in the initial training phase. Here we report function‐transformation effects in the absence of selection responses and of their reinforcers. In three experiments with college students, exposure to relations of difference or identity modified the responses given to later stimuli. In Experiment 1, responses to a test stimulus A varied depending on preexposure to pairs of colors that were distinct from A but exemplified relations of difference or identity. In Experiment 2, a stimulus A acquired distinct functions, depending on its previous pairing with a contextual cue X that had itself been paired with identity or difference among colors. Experiment 3 confirmed the results of Experiment 2 with a modified design. Our data are consistent with the notion that relations of identity or difference can serve as stimuli for Pavlovian processes, and, in compound with other cues, produce apparent function‐transformation effects.
AUTOSHAPED HEAD POKING IN THE MOUSE: A QUANTITATIVE ANALYSIS OF THE LEARNING CURVE
Authors: Papachristos Efstathios B. , Gallistel C. R.
Published: December 2006

In autoshaping experiments, we quantified the acquisition of anticipatory head poking in individual mice, using an algorithm that finds changes in the slope of a cumulative record. In most mice, upward changes in the amount of anticipatory poking per trial were abrupt, and tended to occur at session boundaries, suggesting that the session is as significant a unit of experience as the trial. There were large individual differences in the latency to the onset of vigorous responding. “Asymptotic” performance was unstable; large, bidirectional, and relatively enduring changes were common. Given the characteristics of the individual learning curves, it is unlikely that physiologically meaningful estimates of rate of learning can be extracted from group‐average learning curves.
NOTES ON DISCOUNTING
Authors: Rachlin Howard
Published: December 2006

In general, if a variable can be expressed as a function of its own maximum value, that function may be called a discount function. Delay discounting and probability discounting are commonly studied in psychology, but memory, matching, and economic utility also may be viewed as discounting processes. When they are so viewed, the discount function obtained is hyperbolic in form. In some cases the effective discounting variable is proportional to the physical variable on which it is based. For example, in delay discounting, the physical variable, delay (D), may enter into the hyperbolic equation as kD. In many cases, however, the discounting data are not well described with a single‐parameter discount function. A much better fit is obtained when the effective variable is a power function of the physical variable (kDs in the case of delay discounting). This power‐function form fits the data of delay, probability, and memory discounting as well as other two‐parameter discount functions and is consistent with both the generalized matching law and maximization of a constant‐elasticity‐of‐substitution utility function.
A multidisciplinary approach to determine the structural geometry of hard-rock aquifers. Application to the Plancoet migmatitic aquifer (NE Brittany, W France)
Authors: Durand Véronique , Deffontaines Benoît , Leonardi Véronique , Guerin Roger , Wyns Robert , de Marsily Ghislain , Bonjour Jean-Luc
Published: December 2006

A new multidisciplinary methodology is developed to determine the structural geometry of hard-rock aquifers. The Plancoët migmatitic basement, chosen as an example for the use of this methodology, is studied both at a regional (300 km2) and a local (4 km2) scale. The regional mapping, based on field mapping of the tectonic structures and the weathered layers, on geostatistics and on aerial photographs and Digital Elevation Model (DEM) analyses, demonstrates the influence of the tectonic structures on the weathering processes. Some geo-electric investigations, added to the first mapping at the local scale, lead to the building of a local geometrical model of the aquifer.
The “Schistes carton” of Quercy (Tarn, France): a lithological signature of a methane hydrate dissociation event in the Early Toarcian. Implications for correlations between Boreal and Tethyan realms
Authors: Emmanuel Laurent , Renard Maurice , Cubaynes René , de Rafelis Marc , Hermoso Michael , Lecallonnec Laurence , le Solleuz Antoine , Rey Jacques
Published: December 2006

The geochemical events (negative shifts in δ13C and δ18O, and Mn peak) associated with the “Schistes carton” of Quercy (SW France) do not appear to be due only to lithological variations and a differential diagenesis. They correspond to the Lower Toarcian global event and seem to be connected to a destabilization phase of gas hydrates. During its oxidation by seawater, the release of methane gas with a very low carbon isotopic ratio (− 60%) led to the production of CO2 and carbonates with a negative δ13C. The consumption of oxygen in the seawater resulted in conditions that were first dysoxic and then anoxic. The reduction of burrowing and bioturbation associated with this oxidation resulted in the laminated appearance of the “Schistes carton”. The decrease in the oxygen content led to a decrease in MnO2 microparticles present in the water column and sediments. This created a complementary source of Mn2+ that was incorporated into the carbonates produced during this event. Furthermore, an increase in the average seawater temperature (δ18O) appears associated with this event. Finally, the apparent diachronism of geochemical events in the Boreal and the Tethyan realms is discussed.
Structural evolution of the external zones derived from the Flysch trough and the South Iberian and Maghrebian paleomargins around the Gibraltar arc: a comparative study
Authors: Crespo-Blanc Ana , de Lamotte Dominique Frizon
Published: December 2006

The Betics and Rif cordillera constitute the northern and southern segments of the Gibraltar arc. Two different fold-and-thrust belts, deriving from the South Iberian and Maghrebian paleomargins respectively, developed in front of this orogenic system. By contrast, the Flysch Trough units and the overlying Alboran crustal domain (internal zones), which are situated in the uppermost part of the orogenic wedge, are common to both branches of the arc. The Flyschs Trough units constitute an inactive accretionary prism, derived from a deep elongated trough. From three large-scale profiles and some lithostratigraphic features of the involved sedimentary sequences, the Betic and Rif external domains are compared, mainly from a structural point of view. Although they are generally considered to show major similarities, the Betic and Rif external domains are in fact strikingly different, mainly concerning the structural style, deformation timing and metamorphism: a) the thick-skinned structure in the External Rif domain vs thin-skinned in the Subbetic domain; b) the pre-Oligocene and Miocene stacking in the External Rif domain vs the exclusively Miocene one in the Subbetic domain, and c) the metamorphism present only in part of the External Rif domain (low-grade greenschists facies). By contrast, it was not possible to establish any difference in structural style and deformation timing between the Flysch units outcropping in both branches of the Gibraltar arc.
THE ANTECEDENTS OF HELP GIVING IN CHINESE CULTURE: ATTRIBUTION, JUDGMENT OF RESPONSIBILITY, EXPECTATION CHANGE AND THE REACTION OF AFFECT
Authors: Zhang Aiqing , Xia Feifei , Li Chengwei
Published: December 2006

The quantitative relationships among attributional locus, stability, controllability, judgment of responsibility, affect response and help giving were detected. Participants were 219 employees and managers, and the structural equation model that reflected the relationships among these
variables was tested. The findings suggested that causal locus and controllability linked with help giving are mediated by judgment of responsibility and subsequent affect response and expectation change. Stability attribution indirectly correlated with help giving by linking with expectation.
Attributional dimensions, judgment of responsibility, expectation change and the reactions of affect were the antecedent variables of help giving. Findings are discussed in terms of related Chinese cultural and social values.
GROUP FORMATION IN A SIMULATED SCAVENGER HUNT: HOW BIG AND DIVERSE SHOULD A SUCCESSFUL GROUP BE?
Authors: Harrell W. Andrew
Published: December 2006

Male and female university students (121) received 1 of 8 scenarios describing a hypothetical scavenger hunt. Subjects could form a group to assist them in the hunt or work alone. Groups could be homogeneous or diverse in terms of gender, age, and familiarity. Completion of the task
would result in a prize of 1,000. Subjects indicated how this payoff would be distributed to the group. Twenty minutes or 90 minutes were given to find the designated objects. Their task was also varied in terms of the number of items that needed to be discovered (4 items or 8 items) and whether
or not these items were locally available (on the campus of the university they attended) or were geographically dispersed throughout the surrounding city. Subjects engaged in a two-stage decision process. In the first stage, a decision was made concerning the size of the group formed (if
any) and its homogeneity or diversity in membership. Larger groups were chosen when 8 versus 4 items were gathered and when the items were geographically dispersed. Groups tended to be more diverse when items were dispersed rather than locally concentrated and when time was short (20 minutes).
Payoff division was a second-stage decision. Equity versus equality in distribution was more likely to occur when groups were large and diverse in membership.
GENDER DIFFERENCES IN RELATIONAL AND PHYSICAL AGGRESSION
Authors: Burton Leslie A. , Hafetz Jessica , Henninger Debra
Published: December 2006

A sample of 134 (93 female, 41 male) university students were evaluated with measures of relational and physical aggression, as well as measures of the five personality factors (NEO Five-Factor Inventory; Costa & McCrae, 1992), depression and anxiety (Beck Depression Inventory;
Beck, 1987 and Anxiety Inventory; Beck, 1990), and general emotional understanding and functioning (Bar-On Emotional Quotient Inventory; Bar-On, 1997). Gender differences were found such that the men reported more physical aggression and less Extraversion, with trends for less Neuroticism
and less Agreeableness, than the women (NEO-FFI). Additionally, the women had higher Bar-On Interpersonal overall factor scores, including higher scores for the component Empathy, Social Responsibility, and Interpersonal Relationship subscales, than the men. Relational and physical aggression
showed different patterns of association with other personality and emotional measures for men and women. In men, higher physical aggression was associated with lower Agreeableness and lower Extraversion. In women, higher physical aggression was associated with higher Conscientiousness, more
depression, lower Bar-On EQI Stress Management and higher adaptability. Relational aggression was associated with lower Agreeableness and a lower Bar-On EQI overall score for both men and women. In men, higher relational aggression was additionally associated with more Neuroticism. In women,
higher relational aggression was also associated with lower Conscientiousness, and lower Bar-On EQI Interpersonal factor scores.
METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS RISK PERCEPTION BY HEALTHCARE PERSONNEL IN A PUBLIC HOSPITAL
Authors: Kouabenan Dongo Rémi , Dubois Michel , Gaudemaris Régis de , Scarnato Fabien , Mallaret Marie-Reine
Published: December 2006

This study examines perceived risk of contamination by methicillin-resistant staphylococcus aureus (MRSA) among healthcare personnel in a French university hospital. MRSA poses a public health threat for healthcare staff who work in a hospital environment. This study is part of a pluridisciplinary
research project on the risk factors of MRSA contamination. In many studies (Kouabenan, 1998; Slovic, 1987; Slovic et al., 1981), risk perception appears to be an important factor in understanding attitudes towards accident prevention and selfprotective behavior. A questionnaire measuring
several dimensions of perceived MRSA risk (risk for oneself, risk for others, severity, controllability, frequency, preventive efforts) and a questionnaire assessing optimism were administered to 187 hospital staff members of various occupations. The results revealed that the risk of MRSA
contamination was well perceived as a whole by healthcare personnel. However, certain factors like proximity to patients and length of service tended to be accompanied by an underestimation of the risk, while other factors like little education, working part-time, and a lack of experience
tended to cause overestimation. Preventive measures are recommended.
WHAT PRICE DO YOU ASK FOR THE “EXTRA ONE”?: A SOCIAL VALUE ORIENTATION PERSPECTIVE
Authors: Lin Chien-Huang , Lin Hung-Ming
Published: December 2006

The concept of social value orientation was used to explore individuals' decisions in asking price when they had an “extra one” that someone wanted to buy. Results from an experimental study indicated that competitors' asking price was higher than those of individualists,
who in turn asked higher prices than did prosocials. Regardless of the social value orientation, participants charged a significantly lower price for the “extra one” if the buyer was a friend rather than a stranger. In addition, for prosocials, market price was not an important
consideration when they decided the asking price, and they exhibited cooperative behavior only under the situation of no loss.
Comparison of variability in cardiorespiratory measurements following desflurane anesthesia at a multiple of the minimum alveolar concentration for each dog versus a multiple of a single predetermined minimum alveolar concentration for all dogs in a group
Authors: Pypendop Bruno H. , Ilkiw Jan E.
Published: December 2006

Objective—To determine whether the variability of cardiorespiratory measurements is smaller when administering desflurane at a multiple of the individual's minimum alveolar concentration (MAC) or at a predetermined, identical concentration in all subjects.

Animals—10 dogs.

Procedures—Desflurane was administered at 1.5 times the individual's MAC (iMAC) and 1.5 times the group's MAC (gMAC). The order of concentrations was randomly selected. Heart rate, respiratory rate, arterial blood pressure, central venous pressure, mean pulmonary artery pressure, pulmonary artery occlusion pressure, arterial and mixed-venous blood gas tensions and pH, and cardiac output were measured. The desflurane concentration required to achieve a mean arterial pressure (MAP) of 60 mm Hg was then determined. Finally, the desflurane concentration required to achieve an end-tidal PCO2 of 55 mm Hg was measured.

Results—Variances when administering 1.5 iMAC or 1.5 gMAC were not significantly different for any variable studied. Differences between the MAC multiples needed to reach an MAP of 60 mm Hg and the mean of the sample were significantly larger when gMAC was used, compared with iMAC, indicating that a multiple of iMAC better predicted the concentration resulting in a MAP of 60 mm Hg.

Conclusions and Clinical Relevance—Results suggest that, in a small group of dogs, variability in cardiorespiratory measurements among dogs is unlikely to differ whether an inhalant anesthetic is administered at a multiple of the iMAC in each dog or at an identical gMAC in all dogs.
Effects of ketamine and magnesium on the minimum alveolar concentration of isoflurane in goats
Authors: Queiroz-Castro Patricia , Egger Christine , Redua Marcia A. , Rohrbach Barton W. , Cox Sherry , Doherty Tom
Published: December 2006

Objective—To evaluate the effects of ketamine, magnesium sulfate, and their combination on the minimum alveolar concentration (MAC) of isoflurane (ISO-MAC) in goats.

Animals—8 adult goats.

Procedures—Anesthesia was induced with isoflurane delivered via face mask. Goats were intubated and ventilated to maintain normocapnia. After an appropriate equilibration period, baseline MAC (MACB) was determined and the following 4 treatments were administered IV: saline (0.9% NaCl) solution (loading dose [LD], 30 mL/20 min; constant rate infusion [CRI], 60 mL/h), magnesium sulfate (LD, 50 mg/kg; CRI, 10 mg/kg/h), ketamine (LD, 1 mg/kg; CRI, 25 μg/kg/min), and magnesium sulfate (LD, 50 mg/kg; CRI, 10 mg/kg/h) combined with ketamine (LD, 1 mg/kg; CRI, 25 μg/kg/min); then MAC was redetermined.

Results—Ketamine significantly decreased ISOMAC by 28.7 ± 3.7%, and ketamine combined with magnesium sulfate significantly decreased ISOMAC by 21.1 ± 4.1%. Saline solution or magnesium sulfate alone did not significantly change ISOMAC.

Conclusions and Clinical Relevance—Ketamine and ketamine combined with magnesium sulfate, at doses used in the study, decreased the end-tidal isoflurane concentration needed to maintain anesthesia, verifying the clinical impression that ketamine decreases the end-tidal isoflurane concentration needed to maintain surgical anesthesia. Magnesium, at doses used in the study, did not decrease ISOMAC or augment ketamine's effects on ISOMAC.
Effects of sodium hyaluronate and methylprednisolone acetate on proteoglycan metabolism in equine articular chondrocytes treated with interleukin-1
Authors: Yates Angela C. , Stewart Allison A. , Byron Christopher R. , Pondenis Holly C. , Kaufmann Karissa M. , Constable Peter D.
Published: December 2006

Objective—To determine the effects of sodium hyaluronate (HA) in combination with methylprednisolone acetate (MPA) on interleukin-1 (IL-1)–induced inflammation in equine articular cartilage pellets.

Sample Population—Chondrocytes collected from 7 horses euthanatized for problems unrelated to the musculoskeletal system.

Procedures—Chondrocyte pellets were treated with medium (negative control); medium containing IL-1 (positive control); or medium containing IL-1 with MPA only (0.05 or 0.5 mg/mL), HA only (0.2 or 2 mg/mL), or MPA (0.05 or 0.5 mg/mL) and HA (0.2 or 2 mg/mL) in combination. Proteoglycan (PG) synthesis was determined by incorporation of sulfur 35–labeled sodium sulfate into PGs. Glycosaminoglycan (GAG) content of the media and the pellets and total pellet DNA content were determined.

Results—Methylprednisolone acetate at 0.5 mg/mL caused an increase in PG synthesis, whereas HA had no effect alone. The combination of MPA, both 0.05 mg/mL and 0.5 mg/mL, with HA at 2 mg/mL increased PG synthesis, compared with IL-1–treated control. All treatment groups containing the high concentration of MPA (0.5 mg/mL) and the high concentration of HA (2.0 mg/mL) had pellets with increased GAG content. The addition of HA caused an increase in total GAG content in the media, regardless of MPA treatment. Cyclooxygenase-2 mRNA and aggrecan mRNA expression was significantly reduced with MPA treatment. Total pellet DNA content was unchanged by any treatment.

Conclusions and Clinical Relevance—Our results indicate that MPA in combination with HA has beneficial effects on PG metabolism of IL-1–treated equine chondrocytes.