The Contribution of Commitment Value in Internet Commerce: An Empirical Investigation

Exploring what makes Internet customers satisfied is perhaps one of the most important challenges facing customer relationship managers in this decade. It is important because prior studies suggest that happy customers make repeat purchases and develop brand loyalty. However, there is not enough accumulated knowledge to understand specifically the determinants of customer satisfaction in Internet commerce. To more accurately understand the determinants that may enhance a customer\u27s satisfaction with their Internet shopping experience, this study looks at the customer\u27s commitment value and examines its relationships with the customer\u27s satisfaction. Commitment value is defined as a total value perception from a buyer and is composed of three components: sociopsychological, economic, and product values. The results from this study show that the sociopsychological value (i.e., shopping enjoyment and convenience in purchasing) and the product value (i.e., product quality) contribute significantly to the attainment of customer satisfaction. The economic value (i.e., reduction of time spent in Internet shopping), however, has no significant positive impact on customer satisfaction. Explanations are presented along with the implications

Quantum cavitation in liquid helium

Using a functional-integral approach, we have determined the temperature below which cavitation in liquid helium is driven by thermally assisted quantum tunneling. For both helium isotopes, we have obtained the crossover temperature in the whole range of allowed negative p essures. Our results are compatible with recent experimental results on 4He.Comment: Typeset using Revtex, 10 pages and 2 figures, Phys. Rev B (1996

Anomalous thermoelectric effects of ZrTe5_{5} in and beyond the quantum limit

Thermoelectric effects are more sensitive and promising probes to topological properties of emergent materials, but much less addressed compared to other physical properties. Zirconium pentatelluride (ZrTe$_{5}$) has inspired active investigations recently because of its multiple topological nature. We study the thermoelectric effects of ZrTe$_{5}$ in a magnetic field and find several anomalous behaviors. The Nernst response has a steplike profile near zero field when the charge carriers are electrons only, suggesting the anomalous Nernst effect arising from a nontrivial profile of Berry curvature. Both the thermopower and Nernst signal exhibit exotic peaks in the strong-field quantum limit. At higher magnetic fields, the Nernst signal has a sign reversal at a critical field where the thermopower approaches to zero. We propose that these anomalous behaviors can be attributed to the Landau index inversion, which is resulted from the competition of the $\sqrt{B}$ dependence of the Dirac-type Landau bands and linear-$B$ dependence of the Zeeman energy ($B$ is the magnetic field). Our understanding to the anomalous thermoelectric properties in ZrTe$_{5}$ opens a new avenue for exploring Dirac physics in topological materials.Comment: 6 pages, 4 figure

Biosorption of Pb (II) from aqueous solution by extracellular polymeric substances extracted from Klebsiella sp. J1: Adsorption behavior and mechanism assessment.

The adsorption performance and mechanism of extracellular polymeric substances (EPS) extracted from Klebsiella sp. J1 for soluble Pb (II) were investigated. The maximum biosorption capacity of EPS for Pb (II) was found to be 99.5 mg g(-1) at pH 6.0 and EPS concentration of 0.2 g/L. The data for adsorption process satisfactorily fitted to both Langmuir isotherm and pseudo-second order kinetic model. The mean free energy E and activation energy Ea were determined at 8.22- 8.98 kJ mol(-1) and 42.46 kJ mol(-1), respectively. The liquid-film diffusion step might be the rate-limiting step. The thermodynamic parameters (ΔG(o), ΔH(o) and ΔS(o)) revealed that the adsorption process was spontaneous and exothermic under natural conditions. The interactions between EPS system and Pb (II) ions were investigated by qualitative analysis methods (i.e Zeta potential, FT-IR and EDAX). Based on the strong experimental evidence from the mass balance of the related elements participating in the sorption process, an ion exchange process was identified quantitatively as the major mechanism responsible for Pb (II) adsorption by EPS. Molar equivalents of both K(+) and Mg(2+) could be exchanged with Pb(2+) molar equivalents in the process and the contribution rate of ion exchange to adsorption accounted for 85.72% (Δmequiv = -0.000541)

Comment on 'Geoengineering with seagrasses: Is credit due where credit is given?'

Over the past decade scientists around the world have sought to estimate the capacity of seagrass meadows to sequester carbon, and thereby understand their role in climate change mitigation. The number of studies reporting on seagrass carbon accumulation rates is still limited, but growing scientific evidence supports the hypothesis that seagrasses have been efficiently locking away CO2 for decades to millennia (e.g. Macreadie et al 2014, Mateo et al 1997, Serrano et al 2012). Johannessen and Macdonald (2016), however, challenge the role of seagrasses as carbon traps, claiming that gains in carbon storage by seagrasses may be \u27illusionary\u27 and that \u27their contribution to the global burial of carbon has not yet been established\u27. The authors warn that misunderstandings of how sediments receive, process and store carbon have led to an overestimation of carbon burial by seagrasses. Here we would like to clarify some of the questions raised by Johannessen and Macdonald (2016), with the aim to promote discussion within the scientific community about the evidence for carbon sequestration by seagrasses with a view to awarding carbon credits

Nature-based molecules combined with rivastigmine: A symbiotic approach for the synthesis of new agents against Alzheimer's disease

Starting from nature as original source, new potential agents with pleiotropic activities have been synthesized and evaluated as neuroprotective agents. In this work, novel nature-based hybrids, combining antioxidant motifs with rivastigmine, have been designed and synthesized. The biological results revealed that the new compounds inhibit both AChE and BuChE. In particular, lipoic acid hybrids LA1, LA2, LA3 resulted to be the most potent inhibitors of BuChE showing IC50 values ranging from 340 to 378 nM. Analogously, all the compounds were able to inhibit the self β-amyloid1-42 aggregation. The gallic acid hybrid GA2 as well as the 2-chromonecarboxylic acid hybrids CA1 and CA2 prevented the self-mediated Aβ aggregation with percentages of inhibition ranging from 53% to 59%. Finally, some of them also show potent neuroprotective effects against glutamate-induced cell death and low toxicity in HT22 cells

Effects of over-expression of allene oxide cyclase on camptothecin production by cell cultures of Camptotheca acuminata

Camptothecin (CPT) is an anticancer and antiviral monoterpene-derived indole alkaloid which can be induced by plant hormone, jasmonates. To improve the production of the pharmaceuticals, the jasmonate biosynthesis related gene allene oxide cyclase from Camptotheca acuminate was transferred back into C. acuminate using the method of Agrobacterium-mediated genetic transformation and over expressed. The results of high performance liquid chromatography (HPLC) analysis indicated that the camptothecin content of transgenic callus was higher than that of non-transgenic callus. The highest camptothecin content in transgenic callus was 3.9310 mg/g DW. However, camptothecin content in both transgenic and non-transgenic calli significantly decreased after further extrinsic methyl-jasmonate’s (MeJA's) induction, whereas the content of CPT in transgenic callus was still higher than in non-transgenic one. All the results indicate that endogenic jasmonate's accumulation may be promoted after allene oxide cyclase gene was transformed into C. acuminate and over expressed. In this way, jasmonates can affect second metabolism pathway genes' expression and then the camptothecin content improved. Inexpectantly, the mechanism of extrinsic jasmonate to secondary metabolism of C. acuminate was different from that of endogenic jasmonates.Key words: Agrobacterium tumefaciens, Allene oxide cyclase, Camptotheca acuminata, camptothecin, methyl-jasmonates, transformation

Efficient Autonomous Path Planning for Ultrasonic Non-Destructive Testing: A Graph Theory and K-Dimensional Tree Optimisation Approach

Data Availability Statement: Data are contained within the article.Acknowledgements: This work was enabled through the National Structural Integrity Research Centre (NSIRC), a postgraduate engineering facility for industry-led research into structural integrity established and managed by TWI Ltd. through a network of both national and international universities.Within the domain of robotic non-destructive testing (NDT) of complex structures, the existing methods typically utilise an offline robot-path-planning strategy. Commonly, for robotic inspection, this will involve full coverage of the component. An NDT probe oriented normal to the component surface is deployed in a raster scan pattern. Here, digital models are used, with the user decomposing complex structures into manageable scan path segments, while carefully avoiding obstacles and other geometric features. This is a manual process that requires a highly skilled robotic operator, often taking several hours or days to refine. This introduces several challenges to NDT, including the need for an accurate model of the component (which, for NDT inspection, is often not available), the requirement of skilled personnel, and careful consideration of both the NDT inspection method and the geometric structure of the component. This paper addresses the specific challenge of scanning complex surfaces by using an automated approach. An algorithm is presented, which is able to learn an efficient scan path by taking into account the dimensional constraints of the footprint of an ultrasonic phased-array probe (a common inspection method for NDT) and the surface geometry. The proposed solution harnesses a digital model of the component, which is decomposed into a series of connected nodes representing the NDT inspection points within the NDT process—this step utilises graph theory. The connections to other nodes are determined using nearest neighbour with KD-Tree optimisation to improve the efficiency of node traversal. This enables a trade-off between simplicity and efficiency. Next, movement restrictions are introduced to allow the robot to navigate the surface of a component in a three-dimensional space, defining obstacles as prohibited areas, explicitly. Our solution entails a two-stage planning process, as follows: a modified three-dimensional flood fill is combined with Dijkstra’s shortest path algorithm. The process is repeated iteratively until the entire surface is covered. The efficiency of this proposed approach is evaluated through simulations. The technique presented in this paper provides an improved and automated method for NDT robotic inspection, reducing the requirement of skilled robotic path-planning personnel while ensuring full component coverage.This project was part of an initiative known as AEMRI (Advanced Engineering Materials Research Institute), which is funded by the Welsh European Funding Office (WEFO) using European Regional Development Funds (ERDF) WEFO contract no. 80854

Anomalies of upper critical field in the spinel superconductor LiTi2_2O4−δ_{4-\delta}

High-field electrical transport and point-contact tunneling spectroscopy were used to investigate superconducting properties of the unique spinel oxide, LiTi$_2$O$_{4-\delta}$ films with various oxygen content. We find that the upper critical field $B_\mathrm{c2}$ gradually increases as more oxygen impurities are brought into the samples by carefully tuning the deposition atmosphere. It is striking that although the superconducting transition temperature and energy gap are almost unchanged, an astonishing isotropic $B_\mathrm{c2}$ up to $\sim$ 26 Tesla is observed in oxygen-rich sample, which is doubled compared to the anoxic sample and breaks the Pauli limit. Such anomalies of $B_\mathrm{c2}$ were rarely reported in other three dimensional superconductors. Combined with all the anomalies, three dimensional spin-orbit interaction induced by tiny oxygen impurities is naturally proposed to account for the remarkable enhancement of $B_\mathrm{c2}$ in oxygen-rich LiTi$_2$O$_{4-\delta}$ films. Such mechanism could be general and therefore provides ideas for optimizing practical superconductors with higher $B_\mathrm{c2}$