218 research outputs found
Ferrule-top nanoindenter: An optomechanical fiber sensor for nanoindentation
Ferrule-top probes are self-aligned all-optical devices obtained by fabricating a cantilever on the top of a ferruled optical fiber. This approach has been proven to provide a new platform for the realization of small footprint atomic force microscopes (AFMs) that adapt well to utilization outside specialized laboratories [D. Chavan, Rev. Sci. Instrum. 81, 123702 (2010)10.1063/1.3516044; D. Chavan, Rev. Sci. Instrum. 82, 046107 (2011)10.1063/1.3579496]. In this paper we now show that ferrule-top cantilevers can be also used to develop nanoindenters. Our instrument combines the sensitivity of commercial AFM-based indentation with the ease-of-use of more macroscopic instrumented indenters available today on the market. Furthermore, the all-optical design allows smooth operations also in liquids, where other devices are much more limited and often provide data that are difficult to interpret. This study may pave the way to the implementation of a new generation user-friendly nanoindenters for the measurement of the stiffness of samples in material sciences and medical research. © 2012 American Institute of Physics
Re-assessing the influence of mental intangibility on consumer decision making
The present paper explores the influence of mental intangibility on the size of the consideration set, both on tangible products and services. This research also examines the moderating effect of purchase involvement and objective knowledge on the set. Two experimental studies were conducted to examine these relations. Overall, the results indicate that mental intangibility positively influences the size of the consideration set, regardless of the offering type (product or service). This effect is stronger in low levels of knowledge. Consumer involvement does not seem to have a moderating effect on this relation. This study’s implications and recommendations for future research are also discussed
Consumer Complaints and Company Market Value
Consumer complaints affect company market value and common sense suggests that a negative impact is
expected. However, do complaints always negatively impact company market value? We hypothesize in this
study that complaints may have a non-linear effect on market value. Positive (e.g. avoiding high costs to solve
complaints) and negative (e.g. speedy and intense diffusion) tradeoffs may occur given the level of complaints.
To test our non-linear hypothesis, a panel data was collected from cell phone service providers from 2005 to
2013. The results supported our tradeoff rationale. Low levels of complaints allow for companies to increase
market value, while high levels of complaints cause increasing harm to market value. The sample, model and
period considered in this study, indicates a level of 0.49 complaints per thousand consumers as the threshold for
a shift in tradeoffs. The effects on market value become increasingly negative when trying to make reductions to
move below this level, due to negative tradeoffs
Traditional knowledge and cultural importance of Borassus aethiopum Mart. in Benin: interacting effects of socio-demographic attributes and multi-scale abundance
ResearchBackground: Eliciting factors affecting distribution of traditional knowledge (TK) and cultural importance of plant
resources is central in ethnobiology. Socio-demographic attributes and ecological apparency hypothesis (EAH) have
been widely documented as drivers of TK distribution, but their synergistic effect is poorly documented. Here, we
focused on Borassus aethiopum, a socio-economic important agroforestry palm in Africa, analyzing relationships
between the number of use-reports and cultural importance on one hand, and informant socio-demographic
attributes (age category and gender) on the other hand, considering the EAH at multi-scale contexts. Our
hypothesis is that effects of socio-demographic attributes on use-reports and cultural importance are shaped by
both local (village level) and regional (chorological region level) apparency of study species. We expected so
because distribution of knowledge on a resource in a community correlates to the versatility in the resource
utilization but also connections among communities within a region.
Methods: Nine hundred ninety-two face-to-face individual semi-structured interviews were conducted in six villages of
low versus high local abundance of B. aethiopum spanning three chorological regions (humid, sub-humid and semiarid)
also underlying a gradient of increasing distribution and abundance of B. aethiopum. Number of use-reports and
score of importance of uses of B. aethiopum were recorded in six use-categories including medicine, food, handcraft,
construction, firewood, and ceremonies and rituals. Data were analyzed using Poisson and ordered logistic modelsinfo:eu-repo/semantics/publishedVersio
Warming Can Boost Denitrification Disproportionately Due to Altered Oxygen Dynamics
Background: Global warming and the alteration of the global nitrogen cycle are major anthropogenic threats to the environment. Denitrification, the biological conversion of nitrate to gaseous nitrogen, removes a substantial fraction of the nitrogen from aquatic ecosystems, and can therefore help to reduce eutrophication effects. However, potential responses of denitrification to warming are poorly understood. Although several studies have reported increased denitrification rates with rising temperature, the impact of temperature on denitrification seems to vary widely between systems. Methodology/Principal Findings: We explored the effects of warming on denitrification rates using microcosm experiments, field measurements and a simple model approach. Our results suggest that a three degree temperature rise will double denitrification rates. By performing experiments at fixed oxygen concentrations as well as with oxygen concentrations varying freely with temperature, we demonstrate that this strong temperature dependence of denitrification can be explained by a systematic decrease of oxygen concentrations with rising temperature. Warming decreases oxygen concentrations due to reduced solubility, and more importantly, because respiration rates rise more steeply with temperature than photosynthesis. Conclusions/Significance: Our results show that denitrification rates in aquatic ecosystems are strongly temperature dependent, and that this is amplified by the temperature dependencies of photosynthesis and respiration. Our result
CAM-related changes in chloroplastic metabolism of Mesembryanthemum crystallinum L.
Crassulacean acid metabolism (CAM) is an intriguing metabolic strategy to maintain photosynthesis under conditions of closed stomata. A shift from C3 photosynthesis to CAM in Mesembryanthemum crystallinum plants was induced by high salinity (0.4 M NaCl). In CAM-performing plants, the quantum efficiencies of photosystem II and I were observed to undergo distinct diurnal fluctuations that were characterized by a strong decline at the onset of the day, midday recovery, and an evening drop. The temporal recovery of both photosystems’ efficiency at midday was associated with a more rapid induction of the electron transport rate at PSII. This recovery of the photosynthetic apparatus at midday was observed to be accompanied by extreme swelling of thylakoids. Despite these fluctuations, a persistent effect of CAM was the acceptor side limitation of PSI during the day, which was accompanied by a strongly decreased level of Rubisco protein. Diurnal changes in the efficiency of photosystems were parallel to corresponding changes in the levels of mRNAs for proteins of PSII and PSI reaction centers and for rbcL, reaching a maximum in CAM plants at midday. This might reflect a high demand for new protein synthesis at this time of the day. Hybridization of run-on transcripts with specific probes for plastid genes of M. crystallinum revealed that the changes in plastidic mRNA levels were regulated at the level of transcription
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