Objective: Self-report measures are typically used to assess the effectiveness of road safety advertisements. However, psychophysiological measures of persuasive processing (i.e., skin conductance response [SCR]) and objective driving measures of persuasive outcomes (i.e., in-vehicle Global Positioning System [GPS] devices) may provide further insights into the effectiveness of these advertisements. This study aimed to explore the persuasive processing and outcomes of 2 anti-speeding advertisements by incorporating both self-report and objective measures of speeding behavior. In addition, this study aimed to compare the findings derived from these different measurement approaches.
Methods: Young drivers (N = 20, M age = 21.01 years) viewed either a positive or negative emotion–based anti-speeding television advertisement. While viewing the advertisement, SCR activity was measured to assess ad-evoked arousal responses. The RoadScout GPS device was then installed in participants' vehicles for 1 week to measure on-road speed-related driving behavior. Self-report measures assessed persuasive processing (emotional and arousal responses) and actual driving behavior.
Results: There was general correspondence between the self-report measures of arousal and the SCR and between the self-report measure of actual driving behavior and the objective driving data (as assessed via the GPS devices).
Conclusions: This study provides insights into how psychophysiological and GPS devices could be used as objective measures in conjunction with self-report measures to further understand the persuasive processes and outcomes of emotion-based anti-speeding advertisements. 相似文献
The present study evaluates the tolerance and accumulation potential of Vitis vinifera ssp. sylvestris under moderate and high external Cu levels. A greenhouse experiment was conducted in order to investigate the effects of a range of external Cu concentrations (0–23 mmol L−1) on growth and photosynthetic performance by measuring gas exchange, chlorophyll fluorescence parameters and photosynthetic pigments. We also measured the total copper, nitrogen, phosphorus, sulphur, calcium, magnesium, iron, potassium and sodium concentrations in the plant tissues. All the experimental plants survived even with external Cu concentrations as high as 23 mmol L−1 (1500 mg Cu L−1), although the excess of metal resulted in a biomass reduction of 35%. The effects of Cu on growth were linked to a reduction in net photosynthesis, which may be related to the effect of the high concentration of the metal on photosynthetic electron transport. V. vinifera ssp. sylvestris survived with leaf Cu concentrations as high as 80 mg kg−1 DW and growth parameters were unaffected by leaf tissue concentrations of 35 mg Cu kg−1 DW. The results of our study indicate that plants of V. vinifera ssp. sylvestris from the studied population are more tolerant to Cu than the commercial varieties of grapevine that have been studied in the literature, and could constitute a basis for the genetic improvement of Cu tolerance in grapevine. 相似文献
Plants of one evergreen oak (Quercus ilex) and three deciduous oaks (Q. faginea, with small leaves; Q. pyrenaica and Q. robur, with large leaves) were exposed both to filtered air and to enhanced ozone levels in Open-Top Chambers. Q. faginea and Q. pyrenaica were studied for the first time. Based on visible injury, gas exchange, chlorophyll content and biomass responses, Q. pyrenaica was the most sensitive species, and Q. ilex was the most tolerant, followed by Q. faginea. Functional leaf traits of the species were related to differences in sensitivity, while accumulated ozone flux via stomata (POD1.6) partly contributed to the observed differences. For risk assessment of Mediterranean vegetation, the diversity of responses detected in this study should be taken into account, applying appropriate critical levels. 相似文献
In this study we tested and compared a multiplicative stomatal model and a coupled semi-empirical stomatal-photosynthesis model in their ability to predict stomatal conductance to ozone (gst) using leaf-level data from oilseed rape (Brassica napus L.) and broccoli (Brassica oleracea L. var. italica Plenck). For oilseed rape, the multiplicative model and the coupled model were able to explain 72% and 73% of the observed gst variance, respectively. For broccoli, the models were able to explain 53% and 51% of the observed gst variance, respectively. These results support the coupled semi-empirical stomatal-photosynthesis model as a valid alternative to the multiplicative stomatal model for O3 flux modelling, in terms of predictive performance. 相似文献
Stomatal conductance and net photosynthesis of common milkweed (Asclepias syriaca L.) plants in two different soil moisture regimes were directly quantified and subsequently modeled over an entire growing season. Direct measurements captured the dynamic response of stomatal conductance to changing environmental conditions throughout the day, as well as declining gas exchange and carbon assimilation throughout the growth period beyond an early summer maximum. This phenomenon was observed in plants grown both with and without supplemental soil moisture, the latter of which should theoretically mitigate against harmful physiological effects caused by exposure to ozone. Seasonally declining rates of stomatal conductance were found to be substantial and incorporated into models, making them less susceptible to the overestimations of effective exposure that are an inherent source of error in ozone exposure indices. The species-specific evidence presented here supports the integration of dynamic physiological processes into flux-based modeling approaches for the prediction of ozone injury in vegetation. 相似文献
Forest productivity is strongly affected by seasonal weather patterns and by natural or anthropogenic disturbances. However weather effects on forest productivity are not currently represented in inventory-based models such as CBM-CFS3 used in national forest C accounting programs. To evaluate different approaches to modelling these effects, a model intercomparison was conducted among CBM-CFS3 and four process models (ecosys, CN-CLASS, Can-IBIS and 3PG) over a 2500 ha landscape in the Oyster River (OR) area of British Columbia, Canada. The process models used local weather data to simulate net primary productivity (NPP), net ecosystem productivity (NEP) and net biome productivity (NBP) from 1920 to 2005. Other inputs used by the process and inventory models were generated from soil, land cover and disturbance records. During a period of intense disturbance from 1928 to 1943, simulated NBP diverged considerably among the models. This divergence was attributed to differences among models in the sizes of detrital and humus C stocks in different soil layers to which a uniform set of soil C transformation coefficients was applied during disturbances. After the disturbance period, divergence in modelled NBP among models was much smaller, and attributed mainly to differences in simulated NPP caused by different approaches to modelling weather effects on productivity. In spite of these differences, age-detrended variation in annual NPP and NEP of closed canopy forest stands was negatively correlated with mean daily maximum air temperature during July-September (Tamax) in all process models (R2 = 0.4-0.6), indicating that these correlations were robust. The negative correlation between Tamax and NEP was attributed to different processes in different models, which were tested by comparing CO2 fluxes from these models with those measured by eddy covariance (EC) under contrasting air temperatures (Ta). The general agreement in sensitivity of annual NPP to Tamax among the process models led to the development of a generalized algorithm for weather effects on NPP of coastal temperate coniferous forests for use in inventory-based models such as CBM-CFS3: NPP′ = NPP − 57.1 (Tamax − 18.6), where NPP and NPP′ are the current and temperature-adjusted annual NPP estimates from the inventory-based model, 18.6 is the long-term mean daily maximum air temperature during July-September, and Tamax is the mean value for the current year. Our analysis indicated that the sensitivity of NPP to Tamax was nonlinear, so that this algorithm should not be extrapolated beyond the conditions of this study. However the process-based methodology to estimate weather effects on NPP and NEP developed in this study is widely applicable to other forest types and may be adopted for other inventory based forest carbon cycle models. 相似文献
While it is well established that stomata close during moisture stress, strong correlations among environmental (e.g., vapor pressure deficit, soil moisture, air temperature, radiation) and internal (e.g., leaf water potential, sap flow, root-shoot signaling) variables obscure the identification of causal mechanisms from field experiments. Models of stomatal control fitted to field data therefore suffer from ambiguous parameter identification, with multiple acceptable (i.e., nearly optimal) model structures emphasizing different moisture status indicators and different processes. In an effort to minimize these correlations and improve parameter and process identification, we conducted an irrigation experiment on red maples (Acer rubrum L.) at Harvard Forest (summers of 2005 and 2006). Control and irrigated trees experienced similar radiative and boundary layer forcings, but different soil moisture status, and thus presumably different diurnal cycles of internal leaf water potential. Measured soil moisture and atmospheric forcing were used to drive a transient tree hydraulic model that incorporated a Jarvis-type leaf conductance in a Penman–Monteith framework with a Cowan-type (resistance and capacitance) tree hydraulic representation. The leaf conductance model included dependence on both leaf matric potential, ΨL (so-called feedback control) and on vapor pressure deficit, D (so-called feedforward control). Model parameters were estimated by minimizing the error between predicted and measured sap flow. The whole-tree irrigation treatment had the effect of elevating measured transpiration during summer dry-downs, demonstrating the limiting effect that subsurface resistance may have on transpiration during these times of moisture stress. From the best fitted model, we infer that during dry downs, moisture stress manifests itself in an increase of soil resistance with a resulting decrease in ΨL, leading to both feedforward and feedback controls in the control trees, but only feedforward control for the irrigated set. Increases in the sum-of-squares error when individual model components were disabled allow us to reject the following three null hypotheses: (1) the f(D) stress is statistically insignificant (p = 0.01); (2) the f(ΨL) stress is statistically insignificant (p = 0.07); and (3) plant storage capacitance is independent of moisture status (p = 0.07). 相似文献