Reasoning about Cardinal Directions between Extended Objects

Direction relations between extended spatial objects are important commonsense knowledge. Recently, Goyal and Egenhofer proposed a formal model, known as Cardinal Direction Calculus (CDC), for representing direction relations between connected plane regions. CDC is perhaps the most expressive qualitative calculus for directional information, and has attracted increasing interest from areas such as artificial intelligence, geographical information science, and image retrieval. Given a network of CDC constraints, the consistency problem is deciding if the network is realizable by connected regions in the real plane. This paper provides a cubic algorithm for checking consistency of basic CDC constraint networks, and proves that reasoning with CDC is in general an NP-Complete problem. For a consistent network of basic CDC constraints, our algorithm also returns a 'canonical' solution in cubic time. This cubic algorithm is also adapted to cope with cardinal directions between possibly disconnected regions, in which case currently the best algorithm is of time complexity O(n^5)

A Comparative Analysis of the Causes of the Heroine's Tragedy in Tess of the D'Urbervilles and A Rose for Emily

From the perspective of feminist theory, this paper absorbs and inherits the existing research results, makes a deep interpretation of the two works, and makes a richer comparison and exploration of the tragic causes of Tess and Emily, which is conducive to a better understanding of the value of the works, revealing the significance of the works, and hoping to provide a new perspective to think for the study of their works and calling on the society to recognize the female subject status and self-identity, then to get rid of the shackles of traditional thoughts and to master the fate of themselves

Which Positive Feedback Matters? The Role of Language Concreteness and Temporal Effect in Continuous Contribution in Open Innovation Community

The feedback mechanism is the basis for motivating users to make continuous contributions in the Open Innovation Community (OIC). Although previous studies have revealed the overall role of positive feedback in promoting continuous user contribution, it is not clear which type of positive feedback is more effective and how it changes over time. To solve these problems, we constructed a research model based on reinforcement theory and took Lego Ideas, a typical OIC, as the research object to crawl users’ ideas and feedback data for empirical analysis. The results confirmed the effect of positive feedback and further demonstrated that, the effectiveness of positive feedback varies based on feedback concreteness and the tenure of the focal user. Our study contributes to the literature on how feedback affects user contributions in online communities by refining the classifications of feedback, and provide practical guidance for companies to motivate users to contributing ideas continuously

Controlled release of an antifouling agent from microcapsules with enhanced mechanical and thermal properties

It is well known that wind energy is abundant at sea so many offshore wind power generators have been installed and used. However, there are a few factors affecting the efficiency and reliability of wind turbines. Biofouling caused by a complex marine environment is one of the problems influencing the state of power generation systems in seawater. Therefore antifouling coatings have to be developed and applied to their surfaces. Microcapsules, which can be incorporated into certain coating materials, are an ideal micro-carrier of antifouling agent to achieve its sustained release. This project aimed to prepare microcapsules with an antifouling agent, which can have a high payload, be mechanically strong, have good thermal conductivity, and can achieve sustained release of the active ingredient. The long-term objectives are to achieve the long-term sustained release of the active ingredient in marine environment and antifouling performance, after the microcapsules are incorporated into marine coating that will then be applied to metal surfaces. In this project, microcapsules consisting of N-Vanillylnonanamide (capsaicin synthetic) in the core, which is an antifouling agent, and cellulose acetate butyrate (CAB) as the shell material have been prepared by solvent evaporation method, based on oil in water (O/W) emulsification in a stirred tank. The effects of formulation and processing conditions on the morphology, size, mechanical properties, thermal properties of microcapsules, release rate of the active ingredient in model liquid have been investigated. The formulation and processing conditions included type of emulsifier, emulsifier concentration, agitation speed, core/shell ratio, metallic coating on the CAB microcapsules with capsaicin synthetic. A range of experimental techniques have been used to characterise the microcapsules, including optical microscopy, Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDS), Malvern particle sizing, micromanipulation, UV-VIS spectrophotometry and laser flash analysis. It has been found that the prepared microcapsules had a matrix structure with multiple cores. Based on the experimental conditions and experimental results, using an emulsifier of polyvinyl alcohol (PVA) with concentration of 0.5%, and agitation speed of 1000 rpm to generate the O/W emulsion produced the microcapsules smaller than 60µm for potentially being incorporated into the coatings, an encapsulation efficiency and the payload reached 80.7% and 16.5%, respectively, which is desirable. As for the mechanical properties, the microcapsules showed elastic and plastic deformations under compression, but not rupture for the experimental conditions investigated due to their matrix structure. The Young’s modulus value of microcapsules, calculated by the Hertz model, decreased significantly with increasing the ratio of core/shell material from 0 to 1/2, w/w, and were all in Mega Pascal scale, which are stiffer compared with many different microcapsules prepared by other researchers. Moreover, cyclohexane was used for accelerating the release of capsaicin synthetic from microcapsules and was found to enable to predict the release profile in water by considering the solubility of capsaicin synthetic in each liquid. Ritger-Peppas Model with n = 0.43 was demonstrated to describe the release kinetics of capsaicin synthetic from the microcapsules well, and it is concluded that the release from the matrix microcapsules was driven by Fickian diffusion. In addition, metallic coating of the microcapsules on their surface were achieved successfully by electroless plating copper after generating a layer of polydopamine based on its selfpolymerisation of dopamine. The microcapsules with copper were proved much stiffer than those without any metallic composition. The thermal conductivities were enhanced up to 7 times by incorporating copper and prolonging the time of both self-polymerising PDA and suspending microcapsules. Thus, the microcapsules with an antifouling agent have been successfully prepared, which showed its sustained release over a few months. And the microcapsules with metal on their surface were prepared by electroless plating copper after generating a layer of polydopamine based on its self-polymerisation of dopamine, achieving the aim of enhancing thermal conductivity of the antifouling microcapsules

Self-assembly of Zein-based microcarrier system for colon-targeted oral drug delivery

The advances in pharmaceutical technology allow for the development of various region-selective delivery systems for oral administration to optimize local and systemic therapy. In this paper, micronization associated with a polymorph modification approach was proposed for improving the solubility of hydrophobic drugs for developing a Zein-based colon-targeted delivery system. A microcarrier based on self-assembled structures of Zein was fabricated via a built-in ultrasonic dialysis process, which displayed high payload of a model drug, indomethacin (Indo), with its optimal crystal form. The possible self-assembly mechanism of Zein/Indo forming porous structure in the ultrasonic dialysis process was attributed to the results of intra- and/or intermolecular interactions between Zein and Indo. The designed microspheres, Zein-Indo@PDA, with a surface coating of polydopamine (PDA) not only rendered them enhanced stability and mechanical resistance but also hindered the premature drug release at undesired sites. This innovative formulation design may offer better chances of colon-targeted release

Identification two novel nacrein-like proteins involved in the shell formation of the Pacific oyster Crassostrea gigas

Nacrein-like proteins have carbonic anhydrase (CA)-like domains, but their coding regions are flanked by inserted repeat sequence, such as Gly-X-Asn. Reportedly, nacrein-like proteins show the highest similarity to human carbonic anhydrase 1(α-CA1), possess CA catalytic functions, and play a key role in shell biomineralization. In the present study, two novel nacrein-like proteins were firstly identified from the shell-forming mantle of the Pacific oyster Crassostrea gigas. With numerous analyses, it was identified and characterized that both the nacrein-like proteins F1 and F2 were secreted and most closely related to the nacrein-like protein of California mussel Mytilus californianus via phylogenetic analysis. RT-PCR analysis showed that the nacrein-like proteins F1 and F2 were expressed in multiple tissues and the expression levels remarkably rose after entering the spat stage, which were basically consistent with the increase of calcite fractions in the total shell volume. Surprisingly, the Gly-X-Asn repeat domain, which is distinctive in most nacrein-like proteins, was absent in the two newly identified nacrein-like proteins in C. gigas and replaced with a series of acidic amino acids (D/E). Regardless, nacrein-like proteins in mollusks seem to be vital to the deposition of calcium carbonate and likely perform diverse functions. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11033-014-3298-z) contains supplementary material, which is available to authorized users