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Selected AbstractsReview Article: Ocular blood flow assessment using continuous laser Doppler flowmetryACTA OPHTHALMOLOGICA, Issue 6 2010Charles E. Riva Acta Ophthalmol. 2010: 88: 622,629 Abstract. This article describes the technique of continuous laser Doppler flowmetry (LDF) as applied to the measurement of the flux of red blood cells in the optic nerve head, iris and subfoveal choroid. Starting with the exposition of the physical principles underlying LDF, we first describe the various devices developed to perform LDF in these vascular beds. We then discuss the clinical protocols, blood flow parameters, calibration procedures, reproducibility and limitations of the LDF technique. Various problems still need to be solved in order to bring to light the full potential of LDF in the assessment of microcirculatory haemodynamics. [source] THE ECONOMICS OF HOMELAND SECURITY EXPENDITURES: FOUNDATIONAL EXPECTED COST-EFFECTIVENESS APPROACHESCONTEMPORARY ECONOMIC POLICY, Issue 1 2007SCOTT FARROW While most economists expect some marginal conditions to result from basic expected value models involving government expenditures and homeland security investments, such models are not readily found in the literature. The article presents six basic models that all incorporate uncertainty; they also capture various problems involving technological limits, behavioral interactions, false negatives and false positives, and decision making with uncertainty and irreversibility. Recent reviews of homeland security programs by the U.S. Government Accountability Office are used to illustrate the relevance of the models.(JEL H100) [source] Alignment and Alliances for Research Institutes Engaged in Product Innovation.CREATIVITY AND INNOVATION MANAGEMENT, Issue 2 2003Two Case Studies Research institutes mainly engage in product innovation for the purpose of applying, testing and usually also transferring knowledge or technology. Managing product innovation processes in this type of environment leads to various problems with the establishment and managent of alliances and alignment. In this paper a systematic analysis of product innovation at two energy research institutes is presented, paying explicit attention to the strategic alliances in terms of alignment mechanisms. The cases illustrate clearly how the research institutes manage their external networks for product innovation, allowing comparison of the strengths and weaknesses of the two research institutes, and an indication of lessons to be learned from each other. The systematic analysis contributes to the identifying of the appropriate product innovaiton objectives to be pursued through strategic alliances, as well as the determination of suitable alignment mechanisms for product innovation. Lessons learned are presented in the area of context and contingency influences, crossing organizational barriers, differences in culture and the balancing of operational effectiveness and strategic flexibility. [source] Virus-evolutionary linear genetic programmingELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 1 2008Kenji Tamura Abstract Many kinds of evolutionary methods have been proposed. GA and GP in particular have demonstrated their effectiveness in various problems recently, and many systems have been proposed. One is Virus-Evolutionary Genetic Algorithm (VE-GA), and the other is Linear Genetic Programming in C (LGPC). The performance of each system has been reported. VE-GA is the coevolution system of host individuals and virus individuals. That can spread schema effectively among the host individuals by using virus infection and virus incorporation. LGPC implements the GP by representing the individuals to one dimension as if GA. LGPC can reduce a search cost of pointer and save machine memory, and can reduce the time to implement GP programs. We have proposed that a system introduce virus individuals in LGPC, and analyzed the performance of the system on two problems. Our system can spread schema among the population, and search solution effectively. The results of computer simulation show that this system can search for solution depending on LGPC applying problem's character compared with LGPC. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(1): 32, 39, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10030 [source] Fatigue Crack Propagation and History Effects Induced by Plasticity,ADVANCED ENGINEERING MATERIALS, Issue 9 2009Sylvie Pommier Abstract For security-relevant components, a fracture mechanics assessment has to be carried out. When complex loading conditions are encountered, various problems arise. Among them the prediction of history effects induced by plasticity remains a difficult task and is the object of this paper. After an overload, for instance, plasticity-induced crack closure is known to decelerate the crack growth. This effect is known to be related to residual stresses ahead of and behind the crack tip. Since residual stresses are related to the material stress,strain behavior, the overload effect may vary significantly from one material to another. Finite-element (FE) methods are commonly employed to model plasticity and were shown to give very satisfactory results. However, if millions of cycles need to be modeled to predict the fatigue behavior of an industrial component, the method becomes computationally too expensive. By employing a multiscale approach, very precise analyses computed by FE methods can be brought to a global scale. The data generated using the FE method enables the identification of a global cyclic elastic-plastic model for the crack tip region. Once this model is identified, it can be employed directly with no need of additional FE computations, resulting in fast computations. This method was employed so as to predict fatigue crack growth under variable amplitude fatigue in steels at room temperatures and correlates well with experimental data. It was also extended so as to model fatigue crack growth in a nickel base superalloy under non-isothermal fatigue-dwell conditions. At present, the method is being extended to mixed-mode variable-amplitude loading conditions. [source] Numerical modeling of creep and creep damage in thin plates of arbitrary shape from materials with different behavior in tension and compression under plane stress conditionsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 11 2009A. Zolochevsky Abstract A constitutive model for describing the creep and creep damage in initially isotropic materials with characteristics dependent on the loading type, such as tension, compression and shear, has been applied to the numerical modeling of creep deformation and creep damage growth in thin plates under plane stress conditions. The variational approach of establishing the basic equations of the plane stress problem under consideration has been introduced. For the solution of two-dimensional creep problems, the fourth-order Runge,Kutta,Merson's method of time integration, combined with the Ritz method and R-functions theory, has been used. Numerical solutions to various problems have been obtained, and the processes of creep deformation and creep damage growth in thin plates of arbitrary shape have been investigated. The influence of tension,compression asymmetry on the stress,strain state and damage evolution, with time, in thin plates of arbitrary shape, has been discussed. Copyright © 2009 John Wiley & Sons, Ltd. [source] Idea divergent editor using analogy: The IDEA systemINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 11 2003Takashi Hayashi In this article, an idea divergent editor using analogy (IDEA) system has been proposed. The analogies between two concepts are learned using a neural network through training. First, the problem that a user wants to solve is input to the proposed IDEA system. Second, the IDEA system can draw effective analogies from a knowledge base containing large-scale and wide-ranging concepts for solutions to various problems. The user chooses one of the analogies. Then, the IDEA system presents questions that prompt the user to analyze the problem with reference to the background of the analogy. Answering the presented questions triggers off an inspiration of a solution. The IDEA system facilitates users' divergent thinking, which creates many fragments of ideas. We performed an experiment to examine the effectiveness of the IDEA system; the number of ideas generated is increased about 1.5,2.0 times using the IDEA system. © 2003 Wiley Periodicals, Inc. [source] Rehabilitation and guidance as reported by women and men who had undergone coronary bypass surgeryJOURNAL OF CLINICAL NURSING, Issue 4 2007Kirsi Koivunen RN Aims and objectives., The purpose of this study was to describe the experience of rehabilitation reported by coronary artery disease patients who had undergone coronary artery bypass surgery. A further purpose was to describe the kind of guidance on rehabilitation that they were given during this period. Methods., The data consisted of thematic questionnaires completed by six women and eight men who had undergone coronary artery bypass surgery. They had recorded their experiences on these questionnaires at one-month intervals for a year after the surgery. The data were analysed using the method of content analysis. Results., On the basis of the results, women had experienced the most balanced period of physical, mental and social rehabilitation during the six months following surgery. Their recovery, however, suffered a setback after the first six months. On the basis of the results, men attained a better balance of physical, mental and social rehabilitation only after the six-month period following surgery. Even men had various problems in their rehabilitation, but their recovery proceeded more smoothly than that of women. Women hoped for more guidance throughout the process of rehabilitation. The support and help from wives had a positive impact on the process of men's recovery. Peer support was another significant source support. Conclusions., A person undergoing rehabilitation needs special guidance from health care professionals, especially when his/her rehabilitation does not proceed optimally. The findings suggest that, especially, the guidance of women should be improved because women seemed to suffer from many problems during their process of rehabilitation, including loneliness, insecurity, uncertainty, fears, depression and anxiety. Relevance to clinical practice., Expanding the role of practical nurses to provide both preventive and rehabilitation guidance should be seen as an important strategy in health care. Individual needs, gender differences and support from families and peers should be taken into consideration when planning and implementing guidance. [source] How the choice of a computational model could rule the chemical interpretation: The Ni(II) catalyzed ethylene dimerization as a case studyJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 5 2010Vincent Tognetti Abstract In this article, we present a critical study of the theoretical protocol used for the determination of the nickel(II) catalyzed ethylene dimerization mechanism, considered as a representative example of the various problems related to the modeling a catalytic cycle. The choice of an appropriate computational procedure is indeed crucial for the validity of the conclusions that will be drawn from the computational process. The influence of the exchange-correlation functional on energetic profiles and geometries, the role of the basis set describing the metal atom, as well as the importance of the chosen molecular model, have been thus examined in details. From the obtained results, some general conclusions and guidelines are presented, which could constitute useful warnings in modeling homogenous catalysis. Besides, the database constituted by our high-level calculations can be used within benchmarking procedures to assess the performances of new computational methods based on density functional theory. © 2009 Wiley Periodicals, Inc. J Comput Chem 2010 [source] WHAT DO WE KNOW ABOUT THE PROFITABILITY OF TECHNICAL ANALYSIS?JOURNAL OF ECONOMIC SURVEYS, Issue 4 2007Cheol-Ho Park Abstract The purpose of this paper is to review the evidence on the profitability of technical analysis. The empirical literature is categorized into two groups, ,early' and ,modern' studies, according to the characteristics of testing procedures. Early studies indicate that technical trading strategies are profitable in foreign exchange markets and futures markets, but not in stock markets. Modern studies indicate that technical trading strategies consistently generate economic profits in a variety of speculative markets at least until the early 1990s. Among a total of 95 modern studies, 56 studies find positive results regarding technical trading strategies, 20 studies obtain negative results, and 19 studies indicate mixed results. Despite the positive evidence on the profitability of technical trading strategies, most empirical studies are subject to various problems in their testing procedures, e.g. data snooping, ex post selection of trading rules or search technologies, and difficulties in estimation of risk and transaction costs. Future research must address these deficiencies in testing in order to provide conclusive evidence on the profitability of technical trading strategies. [source] Labile soil organic carbon, soil fertility, and crop productivity as influenced by manure and mineral fertilizers in the tropicsJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 5 2010Siba Prasad Datta Abstract In recent years, organic agriculture has been receiving greater attention because of the various problems like deterioration in soil health and environmental quality under conventional chemical-intensive agriculture. However, little information is available on the comparative study related to the impact of use of mineral fertilizers and organic manures on the soil quality and productivity. A long-term field experiment was initiated in 2001 to monitor some of the important soil-quality parameters and productivity under soybean,wheat crop rotation. The treatments consisted of 0, 30, and 45,kg N ha,1 for soybean and of 0, 120, and 180,kg N ha,1 for wheat. The entire amount of N was supplied to both the crops through urea and farmyard manure (FYM) alone or in combination at 1:1 ratio. Results indicated that Walkley-and-Black C (WBC; chromic acid,oxidizable) exhibited a marginal increase under only organic treatments as compared to control treatment (without fertilizers and manure) after completion of five cropping cycles. In case of labile-C (KMnO4 -oxidizable) content in soil, relatively larger positive changes were recorded under organic, mixed inputs (integrated) and mineral fertilizers as compared to WBC. Maximum improvement in the values of C-management index (CMI), a measure of soil quality was recorded under organic (348,362), followed by mixed inputs (268,322) and mineral fertilizers (198,199) as compared to the control treatment after completion of five cropping cycles. Similarly there was a substantial increase in KCl-extractable N; in Olsen-P; as well as in DTPA-extractable Zn, Fe, and Mn under organic treatments. Although labile soil C positively contributed to the available N, P, K, Zn, Fe, and Mn contents in soil, it did not show any relationship with the grain yield of wheat. After completion of the sixth cropping cycle, organic treatments produced 23% and 39% lower grain yield of wheat as compared to that under urea-treated plots. Relatively higher amount of mineral N in soil at critical growth stages and elevated N content in plant under mineral-fertilizer treatments compared to FYM treatments were responsible for higher yield of wheat under mineral fertilizers. [source] NLPIR: A theoretical framework for applying natural language processing to information retrievalJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 2 2003Lina Zhou The role of information retrieval (IR) in support of decision making and knowledge management has become increasingly significant. Confronted by various problems in traditional keyword-based IR, many researchers have been investigating the potential of natural language processing (NLP) technologies. Despite widespread application of NLP in IR and high expectations that NLP can address the problems of traditional IR, research and development of an NLP component for an IR system still lacks support and guidance from a cohesive framework. In this paper, we propose a theoretical framework called NLPIR that aims at integrating NLP into IR and at generalizing broad application of NLP in IR. Some existing NLP techniques are described to validate the framework, which not only can be applied to current research, but is also envisioned to support future research and development in IR that involve NLP. [source] Opposed bilateral transposition flap: a simple and effective way to close large defects, especially of the limbsJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 5 2008R Verdolini Abstract Background, Excision of large tumours, particularly of the limbs, can be challenging because of problems related to wound repair. This is especially true of the lower legs, where skin is often tight and difficult to mobilize. Closure by flap, which would represent the first choice for defects usually between 12,15 mm to 38,40 mm diameter, is at risk of developing complications, such as end-flap necrosis or dehiscence due to skin tension. For larger defects, usually more than 40 to 45 mm diameter, grafting still remains the only realistic option in the majority of cases, with all the various problems associated with this procedure, such as lengthy healing times and the risk of developing leg ulcers, above all in elderly patients with impaired blood circulation. Second intention healing implies extraordinarily long healing times with often unacceptable delays in normal ambulation and activity. Objective, To find an alternative to the usual repair techniques and to try to reduce the risk of complications. Conclusions, We developed a relatively simple but effective technique for the closure of large wounds resulting from the excision of tumours. Our technique consists of two longitudinal, parallel, transposition flaps obtained from two opposite sides of the wound, with major axes orientated in the cephalic-caudal direction. The two flaps are then rotated around two fulcra placed at two extremes of the wound by approximately 90°. This relatively simple technique has never caused any of the ordinarily associated problems in terms of necrosis or ulcer development. In addition, dehiscence of sutures never occurred, given the fact that suture tension is minimal. Quick healing has resulted in the majority of cases, avoiding all the problems associated with grafting or other traditional flap techniques. [source] Recollections on thrombin generationJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 2 2008H. C. HEMKER Summary., Against an autobiographic background, a historical sketch is given of the development of the technique of thrombin generation, from subsampling to duly calibrated continuous measurement with fluorogenic substrates. Its application to various problems in the pathophysiology of hemostasis and thrombosis is discussed. [source] Lunar dust and lunar simulant activation and monitoringMETEORITICS & PLANETARY SCIENCE, Issue 7 2009William T. WALLACE One of the pressing concerns is the effect that lunar dust (the fraction of the lunar regolith <20 ,m in diameter) will have on systems, both human and mechanical, due to the fact that various problems were caused by dust during the Apollo missions. The loss of vacuum integrity in the lunar sample containers during the Apollo era ensured that the present lunar samples are not in the same condition as they were on the Moon; they have been passivated by oxygen and water vapor. To mitigate the harmful effects of lunar dust on humans, methods of "reactivating" the dust must be developed for experimentation, and, ideally, it should be possible to monitor the level of activity to determine methods of deactivating the dust in future lunar habitats. Here we present results demonstrating that simple grinding, as a simple analog to micrometeorite crushing, is apable of substantially activating lunar dust and lunar simulant, and it is possible to determine the level of chemical activity by monitoring the ability of the dust to produce hydroxyl radicals in aqueous solution. Comparisons between ground samples of lunar dust, lunar simulant, and quartz reveal that ground lunar dust is capable of producing over three times the amount of hydroxyl radicals as lunar simulant and an order of magnitude more than ground quartz. [source] Revisiting the origin of the high metallicities of sub-damped Lyman-alpha systems,MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY: LETTERS (ELECTRONIC), Issue 1 2009Miroslava Dessauges-Zavadsky ABSTRACT Sub-damped Lyman-alpha systems (sub-DLAs) have previously been found to exhibit a steeper metallicity evolution than the classical damped Lyman-alpha systems (DLAs), evolving to close to solar metallicity by z, 1. From new high-resolution spectra of 17 sub-DLAs, we have increased the number of measurements of [Fe/H] at z < 1.7 by 25 per cent and compiled the most complete literature sample of sub-DLA and DLA abundances to date. We find that sub-DLAs are indeed significantly more metal-rich than DLAs, but only at z < 1.7; the metallicity distributions of sub-DLAs and DLAs at z > 1.7 are statistically consistent. We also present the first evidence that sub-DLAs follow a velocity width,metallicity correlation over the same velocity range as DLAs, but the relation is offset to higher metallicities than the DLA relation. On the basis of these results, we revisit the previous explanation that the systematically higher metallicities observed in sub-DLAs are indicative of higher host galaxy masses. We discuss the various problems that this interpretation encounters and conclude that in general sub-DLAs are not uniquely synonymous with massive galaxies. We rule out physically related sources of bias (dust, environment, ionization effects) and examine systematics associated with the selection and analysis of low-redshift sub-DLAs. We propose that the high metallicities of sub-DLAs at z < 1.7 that drives an apparently steep evolution may be due to the selection of most low-redshift sub-DLAs based on their high Mg ii equivalent widths. [source] How far are the left-behind left behind?POPULATION, SPACE AND PLACE (PREVIOUSLY:-INT JOURNAL OF POPULATION GEOGRAPHY), Issue 3 2007A preliminary study in rural China Abstract While the linkage between migration and development has attracted much academic and policy attention, a key aspect of the linkage, namely those left behind in the community of origin, remains under-researched. As one of the first academic attempts to provide a systematic overview of this group in China, this paper describes the basic problems faced by it, discusses the institutional causes of the problems, and explores long-term and short-term solutions. The paper first establishes the fact that, while it seems that individuals decide who migrates and who stays back, there are fundamental institutional constraints on such decisions. The paper then shows that the three main left-behind groups, namely wives, the elderly and children, encounter various problems, but in general their situation is not much worse than that of those living with all family members. Their problems cannot just be attributed to being left-behind individuals; instead, the fundamental cause is that many rural communities as a whole have been left behind economically and socially. Although migration exacerbates the hardship, preventing migration is certainly not a solution. The paper instead calls for measures to redress the urban,rural divide and to improve the provision of public goods in rural communities. Copyright © 2006 John Wiley & Sons, Ltd. [source] Towards a social affordances perspective of media capabilities and interface designPROCEEDINGS OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE & TECHNOLOGY (ELECTRONIC), Issue 1 2007Jason M. Turner This study examined the relationships between collaborative group work and communication technologies. First, a model of experience depicting the most perceptually relevant aspects of group work was produced using self-guided focus groups and survey responses. Eleven elements of the group work context, their interrelationships, and technologies supporting collaborative activity were described. The model suggested communication technologies are situated within contexts of use that affect and are affected by relevant aspects of that context. Participant task groups then resolved various problems using one of three technologies: face-to-face, voice conferencing, or chat. Activity unfolded longitudinally allowing for the emergence of situated actions, interaction, and technology effects. Individual and collective perceptions of how technology affected each element of the model, and how those elements impacted perceptions of technology, were analyzed via in-depth interviews. [source] Representing Space and Objects in Monkeys and ApesCOGNITIVE SCIENCE - A MULTIDISCIPLINARY JOURNAL, Issue 3 2000Josep Call Primate foraging can be construed as a set of interconnected problems that include finding food, selecting efficient travel routes, anticipating the positions of moving prey, and manipulating, and occasionally, extracting food items using tools. The evidence reviewed in this paper strongly suggests that both monkeys and apes use three types of representation (i.e., static, dynamic, and relational) to solve various problems. Static representations involve recalling certain features of the environment, dynamic representations involve imagining changes in the trajectories of moving objects, and relational representations involve encoding the properties of objects in relation to other objects. Contrary to previous claims, no clear differences were found between the representational skills of monkeys and apes. Current evidence also suggests that primates may be better at representing general compared to specific problem features. Finally, we have characterized the domains of space and objects as complementary and indicated future lines of research in these domains. [source] | |||||||||||||||||||||||||