56 research outputs found

    Selective Pod Abortion by \u3ci\u3eBaptista Leucantha\u3c/i\u3e (Fabaceae) as Affected by a Curculionid Seed Predator, \u3ci\u3eApion Rostrum\u3c/i\u3e (Coleoptera)

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    The effect of a seed predator, Apion rostrum (Coleoptera: Curculionidae), on selective pod abortion from Baptisia leucantha (Fabaceae) was investigated in a restored tallgrass prairie plot. Weevil densities in and undamaged seed contents of attached and detached pods were compared over four occasions during the summer of 1993. Detached pods had similar to lower counts of weevils/pod and fewer seeds/pod than attached pods. Weevil density in pods appears only important in promoting pod abortIon through affects on seed number/pod as pods having fewer seeds are selectively aborted

    The inverse relation between risks and benefits: The impact of individual differences in information processing style

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    Existing research shows that evaluations of the risks and benefits of various hazards (i.e., technologies and activities) are inversely related. The affect heuristic explains the negative relation between risks and benefits, as based on the strength of positive or negative affect associated with a hazard. Research on the affect heuristic previously investigated under which conditions people judge risk and benefits independently, focusing on expertise as a factor that might exempt from inversely related judgements of risk and benefits. Measurements within Dual Process Theories have been found to be associated with rational, analytical decision making and accurate judgments. In this paper we investigated the extent to which rational information processing styles can predict the risk-benefit relation of technologies in a medical and food applications and whether the attitudes influence the strength or direction of the relationship. Using the Need for Cognition Scale (NFC), a psychometric-based risk scale and an explicit measure of attitude, in a representative sample of 3228 Swedes, we found that the high NFC group judged the risks and benefits of technologies to be inversely related. In contrast, the low NFC group judged the risks and benefits to be positively related. These results were confirmed across all studied technologies by applying moderation analysis. We discuss the results in light of recent research on cognitive processing and polarization over technologies' risks

    Directions in the development of business tourism in Poland

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    Business tourism in Poland has been developing since the 1990s, when the political regime changed. It is one of the many areas that has been subject to change after the historic year of 1989. However, it gained greater importance in the 21st century. Special attention was to this type of tourism and the product, as, compared to typical tourism oriented towards sightseeing and leisure, business tourists spend more money on travel, as well as in the destination itself, they are the target market for many business entities, and business travel movement takes place throughout the year, fending off the effects of seasonality

    Genetically modified (GM) late blight-resistant potato and consumer attitudes before and after a field visit

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    Late blight, caused by Phytophthora infestans, is the most devastating disease in potato production. Here, we show full late blight resistance in a location with a genetically diverse pathogen population with the use of GM potato stacked with three resistance (R) genes over three seasons. In addition, using this field trials, we demonstrate that in-the-field intervention among consumers led to change for more favorable attitude generally toward GM crops

    The Energy of Muscle Contraction. II. Transverse Compression and Work

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    In this study we examined how the strain energies within a muscle are related to changes in longitudinal force when the muscle is exposed to an external transverse load. We implemented a three-dimensional (3D) finite element model of contracting muscle using the principle of minimum total energy and allowing the redistribution of energy through different strain energy-densities. This allowed us to determine the importance of the strain energy-densities to the transverse forces developed by the muscle. We ran a series of in silica experiments on muscle blocks varying in initial pennation angle, muscle length, and external transverse load. As muscle contracts it maintains a near constant volume. As such, any changes in muscle length are balanced by deformations in the transverse directions such as muscle thickness or muscle width. Muscle develops transverse forces as it expands. In many situations external forces act to counteract these transverse forces and the muscle responds to external transverse loads while both passive and active. The muscle blocks used in our simulations decreased in thickness and pennation angle when passively compressed and pushed back on the load when they were activated. Activation of the compressed muscle blocks led either to an increase or decrease in muscle thickness depending on whether the initial pennation angle was less than or greater than 15°, respectively. Furthermore, the strain energy increased and redistributed across the different strain-energy potentials during contraction. The volumetric strain energy-density varied with muscle length and pennation angle and was reduced with greater transverse load for most initial muscle lengths and pennation angles. External transverse load reduced the longitudinal muscle force for initial pennation angles of β0 = 0°. Whereas for pennate muscle (β0 > 0°) longitudinal force changed (increase or decrease) depending on the muscle length, pennation angle and the direction of the external load relative to the muscle fibres. For muscle blocks with initial pennation angles β0 ≤ 20° the reduction in longitudinal muscle force coincided with a reduction in volumetric strain energy-density

    Subcellular localization and regulation of coenzyme a synthase

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    CoA synthase mediates the last two steps in the sequence of enzymatic reactions, leading to CoA biosynthesis. We have recently identified cDNA for CoA synthase and demonstrated that it encodes a bifunctional enzyme possessing 4'-phosphopantetheine adenylyltransferase and dephospho-CoA kinase activities. Molecular cloning of CoA synthase provided us with necessary tools to study subcellular localization and the regulation of this bifunctional enzyme. Transient expression studies and confocal microscopy allowed us to demonstrate that full-length CoA synthase is associated with the mitochondria, whereas the removal of the N-terminal region relocates the enzyme to the cytosol. In addition, we showed that the N-terminal sequence of CoA synthase ( amino acids 1 - 29) exhibits a hydrophobic profile and targets green fluorescent protein exclusively to mitochondria. Further analysis, involving subcellular fractionation and limited proteolysis, indicated that CoA synthase is localized on the mitochondrial outer membrane. Moreover, we demonstrate for the first time that phosphatidylcholine and phosphatidylethanolamine, which are the main components of the mitochondrial outer membrane, are potent activators of both enzymatic activities of CoA synthase in vitro. Taken together, these data provide the evidence that the final stages of CoA biosynthesis take place on mitochondria and the activity of CoA synthase is regulated by phospholipids

    The Effect of Multidirectional Loading on Contractions of the M. Medial Gastrocnemius

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    Research has shown that compression of muscle can lead to a change in muscle force. Most studies show compression to lead to a reduction in muscle force, although recent research has shown that increases are also possible. Based on methodological differences in the loading design between studies, it seems that muscle length and the direction of transverse loading influence the effect of muscle compression on force production. Thus, in our current study we implement these two factors to influence the effects of muscle loading. In contrast to long resting length of the medial gastrocnemius (MG) in most studies, we use a shorter MG resting length by having participant seated with their knees at a 90° angle. Where previous studies have used unidirectional loads to compress the MG, in this study we applied a multidirectional load using a sling setup. Multidirectional loading using a sling setup has been shown to cause muscle force reductions in previous research. As a result of our choices in experimental design we observed changes in the effects of muscle loading compared to previous research. In the present study we observed no changes in muscle force due to muscle loading. Muscle thickness and pennation angle showed minor but significant increases during contraction. However, no significant changes occurred between unloaded and loaded trials. Fascicle thickness and length showed different patterns of change compared to previous research. We show that muscle loading does not result in force reduction in all situations and is possibly linked to differences in muscle architecture and muscle length

    The Energy of Muscle Contraction. I. Tissue Force and Deformation During Fixed-End Contractions

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    During contraction the energy of muscle tissue increases due to energy from the hydrolysis of ATP. This energy is distributed across the tissue as strain-energy potentials in the contractile elements, strain-energy potential from the 3D deformation of the base-material tissue (containing cellular and extracellular matrix effects), energy related to changes in the muscle\u27s nearly incompressible volume and external work done at the muscle surface. Thus, energy is redistributed through the muscle\u27s tissue as it contracts, with only a component of this energy being used to do mechanical work and develop forces in the muscle\u27s longitudinal direction. Understanding how the strain-energy potentials are redistributed through the muscle tissue will help enlighten why the mechanical performance of whole muscle in its longitudinal direction does not match the performance that would be expected from the contractile elements alone. Here we demonstrate these physical effects using a 3D muscle model based on the finite element method. The tissue deformations within contracting muscle are large, and so the mechanics of contraction were explained using the principles of continuum mechanics for large deformations. We present simulations of a contracting medial gastrocnemius muscle, showing tissue deformations that mirror observations from magnetic resonance imaging. This paper tracks the redistribution of strain-energy potentials through the muscle tissue during fixed-end contractions, and shows how fibre shortening, pennation angle, transverse bulging and anisotropy in the stress and strain of the muscle tissue are all related to the interaction between the material properties of the muscle and the action of the contractile elements

    Tailored communication changes consumers' attitudes and product preferences for genetically modified food

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    Despite scientific consensus, consumers' misperceptions about the risks of genetically modified (GM) food influence product rejection and the persistence of negative attitudes. Building on the mental models approach for risk communication and the Elaboration Likelihood Model for attitude change, a two-wave repeated measures randomized controlled experiment on a representative sample of Swedish consumers was used to test the effectiveness of tailored (to consumers' mental models of GM food) and persuasive (strong vs. weak) communication for attitudes and product preferences change. In wave 1 (N = 3,243) and wave 2 (N = 1,554), we measured consumers' attitudes and elicited product preferences using a discrete choice experiment. We found a positive effect of communication on attitudes and product preferences in two out of the four treatment groups, one of which initially held a negative attitude and perceived GM food as very risky
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