1,047 research outputs found
Exploring efficacy in personal constraint negotiation: an ethnography of mountaineering tourists
Limited work has explored the relationship between efficacy and personal constraint negotiation for adventure tourists, yet efficacy is pivotal to successful activity participation as it influences people’s perceived ability to cope with constraints, and their decision to use negotiation strategies. This paper explores these themes with participants of a commercially organised mountaineering expedition. Phenomenology-based ethnography was adopted to appreciate the social and cultural mountaineering setting from an emic perspective. Ethnography is already being used to understand adventure participation, yet there is considerable scope to employ it further through researchers immersing themselves into the experience. The findings capture the interaction between the ethnographer and the group members, and provide an embodied account using their lived experiences. Findings reveal that personal mountaineering skills, personal fitness, altitude sickness and fatigue were the four key types of personal constraint. Self-efficacy, negotiation-efficacy and other factors, such as hardiness and motivation, influenced the effectiveness of negotiation strategies. Training, rest days, personal health, and positive self-talk were negotiation strategies. A conceptual model illustrates these results and demonstrates the interplay between efficacy and the personal constraint negotiation journey for led mountaineers
Phenotypic plasticity of nest timing in a post‐glacial landscape: how do reptiles adapt to seasonal time constraints?
Life histories evolve in response to constraints on the time available for growth and development. Nesting date and its plasticity in response to spring temperature may therefore be important components of fitness in oviparous ectotherms near their northern range limit, as reproducing early provides more time for embryos to complete development before winter. We used data collected over several decades to compare air temperature and nest date plasticity in populations of painted turtles and snapping turtles from a relatively warm environment (southeastern Michigan) near the southern extent of the last glacial maximum to a relatively cool environment (central Ontario) near the northern extent of post‐glacial recolonization. For painted turtles, population‐level differences in reaction norm elevation for two phenological traits were consistent with adaptation to time constraints, but no differences in reaction norm slopes were observed. For snapping turtle populations, the difference in reaction norm elevation for a single phenological trait was in the opposite direction of what was expected under adaptation to time constraints, and no difference in reaction norm slope was observed. Finally, among‐individual variation in individual plasticity for nesting date was detected only in the northern population of snapping turtles, suggesting that reaction norms are less canalized in this northern population. Overall, we observed evidence of phenological adaptation, and possibly maladaptation, to time constraints in long‐lived reptiles. Where present, (mal)adaptation occurred by virtue of differences in reaction norm elevation, not reaction norm slope. Glacial history, generation time, and genetic constraint may all play an important role in the evolution of phenological timing and its plasticity in long‐lived reptiles
Characterization of antibodies in single-chain format against the E7 oncoprotein of the Human papillomavirus type 16 and their improvement by mutagenesis
BACKGROUND: Human papillomaviruses (HPV) are the etiological agents of cervical cancer. The viral E7 protein plays a crucial role in viral oncogenesis. Many strategies have been explored to block the E7 oncoprotein activity. The single-chain variable antibody fragments (scFvs) are valuable tools in cancer immunotherapy and can be used as "intracellular antibodies" to knock out specific protein functions. For both in vivo and in vitro employment, the scFv intrinsic solubility and stability are important to achieve long-lasting effects. Here we report the characterization in terms of reactivity, solubility and thermal stability of three anti-HPV16 E7 scFvs. We have also analysed the scFv43 sequence with the aim of improving stability and then activity of the antibody, previously shown to have antiproliferative activity when expressed in HPV16-positive cells. METHODS: The three anti-HPV16 E7 scFv 32, 43 51 were selected from the ETH-2 "phage-display" library. Thermal stability was evaluated with ELISA by determining the residual activity of each purified scFv against the recombinant HPV16 E7, after incubation in the presence of human seroalbumine for different time-intervals at different temperatures. Sequence analysis of the scFvs was performed with BLAST and CLUSTALL programs. The scFv43 aminoacid changes were reverted back to the consensus sequence from the immunoglobuline database by site-directed mutagenesis. ScFv solubility was evaluated with Western blotting by determining their relative amounts in the soluble and insoluble fractions of both prokaryotic and eukaryotic systems. RESULTS: ScFv51 was the most thermally stable scFv considered. Sequence analysis of the most reactive scFv43 has evidenced 2 amino acid changes possibly involved in molecule stability, in the VH and VL CDR3 regions respectively. By mutagenesis, two novel scFv43-derived scFvs were obtained, scFv43 M1 and M2. ScFv43 M2 showed to have improved thermal stability and solubility in comparison with the parental scFv43. CONCLUSION: The characterization of 5 specific anti-HPV16 E7 scFvs shows features important for their activity in vivo. ScFv43 M2 shows higher thermal stability with respect to the parental scFv43, and scFv51 shows high stability and solubility. These properties make the 2 scFvs the best candidates to be tested for anti-E7 activity in vivo
Design criteria of the bolometer diagnostic for steady-state operation of the W7-X stellarator
A bolometric diagnostic system with features necessary for steady-state operation in the superconducting stellarator W7-X was designed. During a pulse length of 1800 s with an ECRH (electron cyclotron resonance heating) power of 10 MW, the components suffer not only from a large thermal load but also from stray radiation of the nonabsorbed isotropic microwaves. This paper gives an overview of the technical problems encountered during the design work and the solutions to individual problems to meet the special requirements in W7-X, e.g., component thermal protection, detector offset thermal drift suppression, as well as a microwave shielding technique. © 2010 American Institute of Physic
The Agricultural Model Intercomparison and Improvement Project (AgMIP): Protocols and Pilot Studies
The Agricultural Model Intercomparison and Improvement Project (AgMIP) is a major international effort linking the climate, crop, and economic modeling communities with cutting-edge information technology to produce improved crop and economic models and the next generation of climate impact projections for the agricultural sector. The goals of AgMIP are to improve substantially the characterization of world food security due to climate change and to enhance adaptation capacity in both developing and developed countries. Analyses of the agricultural impacts of climate variability and change require a transdisciplinary effort to consistently link state-of-the-art climate scenarios to crop and economic models. Crop model outputs are aggregated as inputs to regional and global economic models to determine regional vulnerabilities, changes in comparative advantage, price effects, and potential adaptation strategies in the agricultural sector. Climate, Crop Modeling, Economics, and Information Technology Team Protocols are presented to guide coordinated climate, crop modeling, economics, and information technology research activities around the world, along with AgMIP Cross-Cutting Themes that address uncertainty, aggregation and scaling, and the development of Representative Agricultural Pathways (RAPs) to enable testing of climate change adaptations in the context of other regional and global trends. The organization of research activities by geographic region and specific crops is described, along with project milestones. Pilot results demonstrate AgMIP's role in assessing climate impacts with explicit representation of uncertainties in climate scenarios and simulations using crop and economic models. An intercomparison of wheat model simulations near Obregn, Mexico reveals inter-model differences in yield sensitivity to [CO2] with model uncertainty holding approximately steady as concentrations rise, while uncertainty related to choice of crop model increases with rising temperatures. Wheat model simulations with midcentury climate scenarios project a slight decline in absolute yields that is more sensitive to selection of crop model than to global climate model, emissions scenario, or climate scenario downscaling method. A comparison of regional and national-scale economic simulations finds a large sensitivity of projected yield changes to the simulations' resolved scales. Finally, a global economic model intercomparison example demonstrates that improvements in the understanding of agriculture futures arise from integration of the range of uncertainty in crop, climate, and economic modeling results in multi-model assessments
Positive relationships between association strength and phenotypic similarity characterize the assembly of mixed-species bird flocks worldwide
Competition theory predicts that local communities should consist of species that are more dissimilar than expected by chance. We find a strikingly different pattern in a multicontinent data set (55 presence-absence matrices from 24 locations) on the composition of mixed-species bird flocks, which are important sub-units of local bird communities the world over. By using null models and randomization tests followed by meta-analysis, we find the association strengths of species in flocks to be strongly related to similarity in body size and foraging behavior and higher for congeneric compared with noncongeneric species pairs. Given the local spatial scales of our individual analyses, differences in the habitat preferences of species are unlikely to have caused these association patterns; the patterns observed are most likely the outcome of species interactions. Extending group-living and social-information-use theory to a heterospecific context, we discuss potential behavioral mechanisms that lead to positive interactions among similar species in flocks, as well as ways in which competition costs are reduced. Our findings highlight the need to consider positive interactions along with competition when seeking to explain community assembly
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