991 resultados para 306.09861
Resumo:
Raman spectra were recorded in the range 400–1800 cm−1 for a series of 15 mixed \[tetrakis(4-tert-butylphenyl)porphyrinato](2,3-naphthalocyaninato) rare earth double-deckers M(TBPP)(Nc) (M = Y; La–Lu except Pm) using laser excitation at 632.8 and 785 nm. Comparisons with bis(naphthalocyaninato) rare earth counterparts reveal that the vibrations of the metallonaphthalocyanine M(Nc) fragment dominate the Raman features of M(TBPP)(Nc). When excited with radiation of 632.8 nm, the most intense vibration appears at about 1595 cm−1, due to the naphthalene stretching. These complexes exhibit the marker Raman band for Nc•− as a medium-intense band in the range 1496–1507 cm−1, attributed to the coupling of pyrrole and aza stretching, while the marker Raman band of Nc2− in intermediate-valence Ce(TBPP)(Nc) appears as a strong band at 1493 cm−1 and is due to the isoindole stretchings. By contrast, when excited with radiation of 785 nm that is in close resonance with the main Q absorption band of the naphthalocyanine ligand, the ring radial vibrations at ca 680 and 735 cm−1 for MIII(TBPP)(Nc) are selectively intensified and are the most intense bands. For the cerium double-decker, the most intense vibration also acting as the marker Raman band of Nc2− appears at 1497 cm−1 with contributions from both pyrrole CC and aza CN stretches. The same vibrational modes show weak to medium intensity scattering at 1506–1509 cm−1 for MIII(TBPP)(Nc) and this is the marker Raman band of Nc•− when thus excited. The scatterings due to the Nc breathings, ring radial vibration, aza group stretchings, naphthalene stretchings, benzoisoindole stretchings and the coupling of pyrrole CC and aza CN stretchings in MIII(TBPP)(Nc) are all slightly blue shifted along with the decrease in rare earth ionic radius, confirming the effects of increased ring–ring interactions on the Raman characteristics of naphthalocyanine in the mixed ring double-deckers.
Resumo:
Purpose – The aim of this paper is to investigate the ways of best managing city-regions’ valuable tangible and intangible assets while pursuing a knowledge-based urban development that is sustainable and competitive. Design/methodology/approach – The paper provides a theoretical framework to conceptualise a new strategic planning mechanism, knowledge-based strategic planning, which has been emerged as a planning mechanism for the knowledge-based urban development of post-industrial city-regions. Originality/value – The paper develops a planning framework entitled 6K1C for knowledge-based strategic planning to be used in the analysis of city-regions’ tangible and intangible assets. Practical implications – The paper discusses the importance of asset mapping of cityregions, and explores the ways of successfully managing city-regions’ tangible/intangible assets to achieve an urban development that is sustainable and knowledge-based. Keywords – Knowledge-based urban development, Knowledge-based strategic planning, Tangible assets, Intangible assets, City-regions. Paper type – Academic Research Paper
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This paper reviews the main development of approaches to modelling urban public transit users’ route choice behaviour from 1960s to the present. The approaches reviewed include the early heuristic studies on finding the least cost transit route and all-or-nothing transit assignment, the bus common line problem and corresponding network representation methods, the disaggregate discrete choice models which are based on random utility maximization assumptions, the deterministic use equilibrium and stochastic user equilibrium transit assignment models, and the recent dynamic transit assignment models using either frequency or schedule based network formulation. In addition to reviewing past outcomes, this paper also gives an outlook into the possible future directions of modelling transit users’ route choice behaviour. Based on the comparison with the development of models for motorists’ route choice and traffic assignment problems in an urban road area, this paper points out that it is rewarding for transit route choice research to draw inspiration from the intellectual outcomes out of the road area. Particularly, in light of the recent advancement of modelling motorists’ complex road route choice behaviour, this paper advocates that the modelling practice of transit users’ route choice should further explore the complexities of the problem.
Resumo:
Background: Increasing attention has been given by researchers to cannabis use in individuals with psychosis. As psychoses are relatively low-prevalence disorders, research has been mostly been restricted to small-scale studies of treatment samples.The reported prevalence estimates obtained from these studies vary widely. Aims: To provide prevalence estimates based on larger samples and to examine sources of variability in prevalence estimates across studies. Method: Data from 53 studies of treatment samples and 5 epidemiological studies were analysed. Results: Based on treatment sample data, prevalence estimates were calculated for current use (23.0%), current misuse (11.3%),12-month use (29.2%),12-month misuse (18.8%), lifetime use (42.1%) and lifetime misuse (22.5%). Epidemiological studies consistently reported higher cannabis use and misuse prevalence in people with psychosis. Conclusions: The factor most consistently associated with increased odds of cannabis prevalence was specificity of diagnosis. Factors such as consumption patterns and study design merit further consideration.
Resumo:
Discusses the importation of Western concepts of corporate governance into Hong Kong where many companies are family companies to which Asian culture is more familiar. Considers different models of corporate governance and questions the application of Western structures to family owned companies. Examines the weaknesses inherent in the typical structure of Asian companies, particularly from the point of view of minority shareholders. Suggests that a system of governance based on Confucian philosophy may be more effective in Hong Kong.
Resumo:
Over many centuries of settlement, Vietnamese inhabitants have developed a vernacular architecture that is well adapted to the region’s climatic and topographical conditions. Vernacular Vietnamese housing uses natural systems to create a built environment that integrates well with nature. The vernacular combines site-sensitive, passive solar design, natural materials and appropriate structure to achieve harmony among nature, humans and the built environment. Unfortunately, these unique features have not been applied in contemporary Vietnamese architecture, which displays energy-intensive materials and built forms. This research is analysing how environmentally-responsive elements of vernacular architecture could be applied to modern sustainable housing in Vietnam. Elements of many types of vernacular architecture throughout the country are reviewed as precedents for future building planning and design. The paper also looks at culturally and ecologically appropriate legislative and voluntary options for encouraging more sustainable housing.
Resumo:
Purpose: This paper aims to show that identification of expectations and software functional requirements via consultation with potential users is an integral component of the development of an emergency department patient admissions prediction tool. ---------- Design/methodology/approach: Thematic analysis of semi-structured interviews with 14 key health staff delivered rich data regarding existing practice and future needs. Participants included emergency department staff, bed managers, nurse unit managers, directors of nursing, and personnel from health administration. ---------- Findings: Participants contributed contextual insights on the current system of admissions, revealing a culture of crisis, imbued with misplayed communication. Their expectations and requirements of a potential predictive tool provided strategic data that moderated the development of the Emergency Department Patient Admissions Prediction Tool, based on their insistence that it feature availability, reliability and relevance. In order to deliver these stipulations, participants stressed that it should be incorporated, validated, defined and timely. ---------- Research limitations/implications: Participants were envisaging a concept and use of a tool that was somewhat hypothetical. However, further research will evaluate the tool in practice. ---------- Practical implications: Participants' unsolicited recommendations regarding implementation will not only inform a subsequent phase of the tool evaluation, but are eminently applicable to any process of implementation in a healthcare setting. ---------- Originality/value: The consultative process engaged clinicians and the paper delivers an insider view of an overburdened system, rather than an outsider's observations.
Resumo:
Wireless Multi-media Sensor Networks (WMSNs) have become increasingly popular in recent years, driven in part by the increasing commoditization of small, low-cost CMOS sensors. As such, the challenge of automatically calibrating these types of cameras nodes has become an important research problem, especially for the case when a large quantity of these type of devices are deployed. This paper presents a method for automatically calibrating a wireless camera node with the ability to rotate around one axis. The method involves capturing images as the camera is rotated and computing the homographies between the images. The camera parameters, including focal length, principal point and the angle and axis of rotation can then recovered from two or more homographies. The homography computation algorithm is designed to deal with the limited resources of the wireless sensor and to minimize energy con- sumption. In this paper, a modified RANdom SAmple Consensus (RANSAC) algorithm is proposed to effectively increase the efficiency and reliability of the calibration procedure.
Resumo:
Of the numerous factors that play a role in fatal pedestrian collisions, the time of day, day of the week, and time of year can be significant determinants. More than 60% of all pedestrian collisions in 2007 occurred at night, despite the presumed decrease in both pedestrian and automobile exposure during the night. Although this trend is partially explained by factors such as fatigue and alcohol consumption, prior analysis of the Fatality Analysis Reporting System database suggests that pedestrian fatalities increase as light decreases after controlling for other factors. This study applies graphical cross-tabulation, a novel visual assessment approach, to explore the relationships among collision variables. The results reveal that twilight and the first hour of darkness typically observe the greatest frequency of pedestrian fatal collisions. These hours are not necessarily the most risky on a per mile travelled basis, however, because pedestrian volumes are often still high. Additional analysis is needed to quantify the extent to which pedestrian exposure (walking/crossing activity) in these time periods plays a role in pedestrian crash involvement. Weekly patterns of pedestrian fatal collisions vary by time of year due to the seasonal changes in sunset time. In December, collisions are concentrated around twilight and the first hour of darkness throughout the week while, in June, collisions are most heavily concentrated around twilight and the first hours of darkness on Friday and Saturday. Friday and Saturday nights in June may be the most dangerous times for pedestrians. Knowing when pedestrian risk is highest is critically important for formulating effective mitigation strategies and for efficiently investing safety funds. This applied visual approach is a helpful tool for researchers intending to communicate with policy-makers and to identify relationships that can then be tested with more sophisticated statistical tools.