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Better Performance (good + performance)
Kinds of Better Performance Terms modified by Better Performance Selected AbstractsBetter Performance of Monodentate P -Stereogenic Phosphanes Compared to Bidentate Analogues in Pd-Catalyzed Asymmetric Allylic AlkylationsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 21 2010Arnald Grabulosa Abstract The cationic allylpalladium complexes 3a,3f, 4a, 4e, 5e of type [Pd(,3 -2-Me-C3H4)P2]PF6 were synthesized using a group of monodentate P -stereogenic phosphanes, P=PPhRR, (a,f) and diphosphanes (PhRPCH2)2 (1a, 1e) or PhRPCH2Si(Me)2CH2PPhR (2e). The analogous cationic complexes with the disubstituted allyl group (,3 -1,3-Ph2 -C3H3) and monodentate phosphanes were not isolated as stable solids; only [PdCl(,3 -1,3-Ph2 -C3H3)P] (6a, 6d) were obtained. Palladium allyl complexes were screened as precatalysts in the allylic substitution of rac -3-acetoxy-1,3-diphenyl-1-propene (I) and (E)-3-acetoxy-1-phenyl-1-propene (III) with dimethyl malonate as the nucleophile. The various catalytic precursors showed a wide range of activity and selectivity. The bismonodentate phosphane complexes 3 are more active than the bidentate analogues. With regard to the regioselectivity, precursors containing monodentate phosphanes favour the formation of the linear product in the allylic substitution of cinnamyl acetate (III) compared with those containing bidentate phosphanes. With substrate I, compounds with the diphosphanes 1a and 1e, containing a five-membered chelate ring, gave low enantioselectivities (less than 10,% ee), but those with the diphosphane 2e, forming a six-membered chelate ring or with two monodentate phosphanes, afforded products with moderate enantioselectivity under standard conditions (ee up to 74,%). The results show that the performance of precursors containing monodentate phosphanes was superior to those containing bidentate ligands in both activity and selectivity. [source] Infrequent sporophyte production maintains a female-biased sex ratio in the unisexual clonal moss Hylocomium splendensJOURNAL OF ECOLOGY, Issue 5 2010Knut Rydgren Summary 1.,Sex ratios in unisexual bryophytes are most often female biased, whereas male-biased sex ratios predominate in unisexual seed plants. This ,bryophyte paradox', i.e. that sex ratios are biased in favour of the sex associated with the highest reproductive costs, has remained unexplained. 2.,Analysis of sex-ratio patterns via the influence of sex distribution on population growth rates (,) has not previously been carried out for bryophytes. We used this method to model how variation in sex ratio and sporophyte frequency influences , in the clonal bryophyte Hylocomium splendens. We obtained , by matrix modelling of synthetic experimental populations derived from demographic field data, using a linear two-sex model. 3.,In our set of experimental populations , varied between 1.13 and 1.27 in response to variation in sex ratio and sporophyte frequency, with the highest , obtained for the combination of a very low sporophyte frequency and a slightly female-biased sex ratio. 4.,Our results explain the female-biased sex ratio of H. splendens by the slightly lower survival of and production of vegetative offspring by males than by non-sporophytic females. 5.,Synthesis. According to our models, female dominance is the predicted outcome of low to moderate fertilization success and male performance intermediate between that of sporophytic and of non-sporophytic females. Our results therefore explain how a female-biased sex ratio can be maintained despite higher costs of reproduction in females than in males. In dioecious bryophytes, males and females must grow in close contact for fertilization to take place. Better performance of male ramets than of the female ramets they fertilize also explains how male clones can expand into female clones. A similar performance hierarchy of males and females may occur in unisexual clonal seed plants, but more efficient fertilization systems by pollination prevents the selective advantage of unfertilized females from being realized. This explains why vascular plant populations tend to be male biased. We hypothesise difference in fertilization distance range between sperm and pollen as a simple explanation why ramet level sex ratios are in general male dominated in clonal seed plants and female dominated in clonal bryophytes. [source] Beta-glucan production by Botryosphaeria rhodina in different bench-top bioreactorsJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2004L. Selbmann Abstract Aims:, Evaluation of the technical feasibility of transferring , -glucan production by Botryosphaeria rhodina DABAC-P82 from shaken flasks to bench-top bioreactors. Methods and Results:, Three different bioreactors were used: 3 l stirred tank reactor (STR-1) equipped with two different six-blade turbines; STR as above but equipped with a three-blade marine propeller plus draft-tube (STR-2); 2 l air-lift column reactor (ALR) equipped with an external loop. STR-1, tested at three different stirrer speeds (300, 500 and 700 rev min,1) appeared to be less suitable for , -glucan production by the fungus, being maximum production (19·4 g l,1), productivity (0·42 g l,1 h,1) and yield (0·48 g g,1 of glucose consumed) markedly lower than those obtained in shaken culture (29·7 g l,1, 1·23 g l,1 h,1 and 0·61 g g,1, respectively). Better performances were obtained with both STR-2 and ALR. With the latter, in particular, the increase of production was accompanied by reduced fermentation time (25·7 g l,1 after only 22 h); productivity and yield were highest (1·17 g l,1 h,1 and 0·62 g g,1 of glucose consumed, respectively). Conclusion:, Using an air-lift reactor with external loop, the scaling up from shaken flasks to bench-top bioreactor of the , -glucan production by B. rhodina DABAC-P82 is technically feasible. Significance and Impact of the Study:, Although culture conditions are still to be optimized, the results obtained using the ARL are highly promising. [source] A positive/negative refractive index coplanar transmission line in CMOS for controlled insertion phaseMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2008Podilchak Symon Abstract A positive/negative refractive index coplanar transmission line is presented and used for phase control in CMOS circuits. Good performance has been achieved. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2227,2230, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23622 [source] APPLYING MACHINE LEARNING TO LOW-KNOWLEDGE CONTROL OF OPTIMIZATION ALGORITHMSCOMPUTATIONAL INTELLIGENCE, Issue 4 2005Tom Carchrae This paper addresses the question of allocating computational resources among a set of algorithms to achieve the best performance on scheduling problems. Our primary motivation in addressing this problem is to reduce the expertise needed to apply optimization technology. Therefore, we investigate algorithm control techniques that make decisions based only on observations of the improvement in solution quality achieved by each algorithm. We call our approach "low knowledge" since it does not rely on complex prediction models, either of the problem domain or of algorithm behavior. We show that a low-knowledge approach results in a system that achieves significantly better performance than all of the pure algorithms without requiring additional human expertise. Furthermore the low-knowledge approach achieves performance equivalent to a perfect high-knowledge classification approach. [source] HIGH-DIMENSIONAL LEARNING FRAMEWORK FOR ADAPTIVE DOCUMENT FILTERING,COMPUTATIONAL INTELLIGENCE, Issue 1 2003Wai Lam We investigate the unique requirements of the adaptive textual document filtering problem and propose a new high-dimensional on-line learning framework, known as the REPGER (relevant feature pool with good training example retrieval rule) algorithm to tackle this problem. Our algorithm possesses three characteristics. First, it maintains a pool of selective features with potentially high predictive power to predict document relevance. Second, besides retrieving documents according to their predicted relevance, it also retrieves incoming documents that are considered good training examples. Third, it can dynamically adjust the dissemination threshold throughout the filtering process so as to maintain a good filtering performance in a fully interactive environment. We have conducted experiments on three document corpora, namely, Associated Press, Foreign Broadcast Information Service, and Wall Street Journal to compare the performance of our REPGER algorithm with two existing on-line learning algorithms. The results demonstrate that our REPGER algorithm gives better performance most of the time. Comparison with the TREC (Text Retrieval Conference) adaptive text filtering track participants was also made. The result shows that our REPGER algorithm is comparable to them. [source] A comparative study of student performance in traditional mode and online mode of learningCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 1 2007Qiping Shen Abstract There has been interest for many decades in comparing the effectiveness of technology-delivered instruction with traditional face-to-face teaching and measurable student outcomes have been an important indicator. Having pointed to salient aspects of the current academic environment and to some of the key literature in this area, this article analyses the performance of two groups of students studying in the traditional mode and the online mode in a masters program delivered by a Department of Computing at a university in Hong Kong. Over 2,000 students have participated in the study between 2000 and 2004. This article includes a comparison of the results between different delivery modes of study each year as well as between different classes over the 4-year period. Although traditional mode students have achieved a slightly better performance in examinations in comparison with online mode students, the article concludes that there are no significant differences in overall performance between the students. With the impact of technologies on higher education and the demands of a complex and rapidly changing society in the 21st century, this Hong Kong study contributes to the literature that finds mode of study is not a key determinant of success. © 2007 Wiley Periodicals, Inc. Comput Appl Eng Educ 15: 30,40, 2007; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20092 [source] Efficient resource discovery in self-organized unstructured peer-to-peer networksCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 2 2009Lu Liu Abstract In unstructured peer-to-peer (P2P) networks, two autonomous peer nodes can be connected if users in those nodes are interested in each other's data. Owing to the similarity between P2P networks and social networks, where peer nodes can be regarded as people and connections can be regarded as relationships, social strategies are useful for improving the performance of resource discovery by self-organizing autonomous peers on unstructured P2P networks. In this paper, we present an efficient social-like peer-to-peer (ESLP) method for resource discovery by mimicking different human behaviours in social networks. ESLP has been simulated in a dynamic environment with a growing number of peer nodes. From the simulation results and analysis, ESLP achieved better performance than current methods. Copyright © 2008 John Wiley & Sons, Ltd. [source] Performance analysis of high-performance file-transfer systems for Grid applicationsCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 8 2006Cosimo Anglano Abstract Data-intensive Grid applications require the availability of tools able to transfer very large files in the shortest amount of time. Many file-transfer tools, based on solutions aimed at overcoming the limitations imposed by the TCP protocol, have recently been developed. In this paper we experimentally compare the performance of some of these tools in various network scenarios by running experiments on PlanetLab, an open platform for the development, deployment, and access of planetary-scale services, that comprises hundreds of hosts scattered across the globe. Our results show that solutions based on UDP and adopting rate-based algorithms result in better performance than other alternatives in most cases, while solutions based on TCP achieve similar performance only under specific circumstances. Copyright © 2005 John Wiley & Sons, Ltd. [source] Simulation of resource synchronization in a dynamic real-time distributed computing environmentCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 14 2004Chen Zhang Abstract Today, more and more distributed computer applications are being modeled and constructed using real-time principles and concepts. In 1989, the Object Management Group (OMG) formed a Real-Time Special Interest Group (RT SIG) with the goal of extending the Common Object Request Broker Architecture (CORBA) standard to include real-time specifications. This group's most recent efforts have focused on the requirements of dynamic distributed real-time systems. One open problem in this area is resource access synchronization for tasks employing dynamic priority scheduling. This paper presents two resource synchronization protocols that the authors have developed which meet the requirements of dynamic distributed real-time systems as specified by Dynamic Scheduling Real-Time CORBA (DSRT CORBA). The proposed protocols can be applied to both Earliest Deadline First (EDF) and Least Laxity First (LLF) dynamic scheduling algorithms, allow distributed nested critical sections, and avoid unnecessary runtime overhead. In order to evaluate the performance of the proposed protocols, we analyzed each protocol's schedulability. Since the schedulability of the system is affected by numerous system configuration parameters, we have designed simulation experiments to isolate and illustrate the impact of each individual system parameter. Simulation experiments show the proposed protocols have better performance than one would realize by applying a schema that utilizes dynamic priority ceiling update. Copyright © 2004 John Wiley & Sons, Ltd. [source] A comparison of concurrent programming and cooperative multithreadingCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 1 2003Aaron W. Keen Abstract This paper presents a comparison of the cooperative multithreading model with the general concurrent programming model. It focuses on the execution time performance of a range of standard concurrent programming applications. The overall results are mixed. In some cases, programs written in the cooperative multithreading model outperform those written in the general concurrent programming model. The contributions of this paper are twofold. First, it presents a thorough analysis of the performances of applications in the different models, i.e. to explain the criteria that determine when a program in one model will outperform an equivalent program in the other. Second, it examines the tradeoffs in writing programs in the different programming styles. In some cases, better performance comes at the cost of more complicated code. Copyright © 2003 John Wiley & Sons, Ltd. [source] Introduction Strategies Put to the Test: Local Adaptation versus HeterosisCONSERVATION BIOLOGY, Issue 3 2004PHILIPPINE VERGEER exogamia; introducciones multi-fuente; introducciones uni-fuente; Succisa pratensis Abstract:,Plant biodiversity has declined seriously because of both habitat deterioration and habitat fragmentation. As a result, many species have been forced into small, fragmented, and isolated populations and are believed to suffer from higher extinction risks. Genetic reinforcement and the establishment of new populations are now widely used to prevent extinction. However, the genetic background of transplants may seriously affect the long-term success of these populations because increased genetic variation may reduce the risk of inbreeding or lead to better performance by restored heterozygosity levels (heterosis). Introduced transplants, however, may be poorly adapted to the new local conditions. We tested the initial success of alternative introduction strategies. We evaluated the potential for inbreeding, heterosis, and/or local adaptation after introduction of artificial populations of Succisa pratensis. We introduced individuals from local and distant artificial populations that were created from either small or large populations. We created the artificial populations with the same census population size but varying effective population sizes by adjusting the relatedness of individuals. We analyzed the demographic consequences of inbreeding, heterosis, and/or local adaptation of these artificial populations. Reduced performance after selfing was manifested by a reduction in seed production, seed weight, germination, and flowering percentage. Seed production, seed weight, flowering percentage, and number of flowerheads were negatively affected by small population size. Local adaptation increased biomass and flowering percentage for local individuals. Seed weight and seed production exhibited significant heterosis. Our results demonstrate that threatened populations can benefit from introduction and genetic reinforcement of individuals from related populations. Significant differences among the artificial populations for several measured performance components suggest that introduction or reinforcement is best achieved through material from a local population or, when unavailable, from several large populations. Resumen:,La biodiversidad de plantas ha declinado seriamente tanto por el deterioro como la fragmentación de hábitats. Como resultado, muchas especies han sido relegadas a poblaciones pequeñas, fragmentadas y aisladas cuyos riesgos de extinción se piensa que son mayores. El reforzamiento genético y el establecimiento de poblaciones nuevas se utilizan ampliamente en la actualidad para prevenir la extinción. Sin embargo, los antecedentes genéticos de transplantes pueden afectar seriamente el éxito de estas poblaciones a largo plazo debido a que el incremento en la variación genética puede reducir el riesgo de endogamia o puede conducir a un mejor rendimiento por lograr niveles de heterocigosidad restaurados (heterosis). No obstante, los trasplantes introducidos pueden adaptarse deficientemente a las nuevas condiciones locales. Probamos el éxito inicial de estrategias de introducción alternativas. Evaluamos el potencial de endogamia, heterosis y/o adaptación local después de la introducción de poblaciones artificiales de Succisa pratensis. Introdujimos individuos de poblaciones locales y de poblaciones artificiales distantes que fueron creadas a partir de poblaciones tanto pequeñas como grandes. Las poblaciones artificiales fueron creadas con el mismo tamaño poblacional censal pero variaron en tamaños poblacionales efectivos al ajustar la parentela de los individuos. Analizamos las consecuencias demográficas de la endogamia, heterosis y/o adaptación local de estas poblaciones artificiales. Después de la autofecundación se manifestó una reducción en el rendimiento por reducción en la producción y peso de semillas y en el porcentaje de germinación y floración. La producción y peso de semillas, el porcentaje de floración y el número de botones florales fueron afectados negativamente por el tamaño poblacional pequeño. La adaptación local incrementó la biomasa y el porcentaje de floración en individuos locales. El peso y producción de semillas mostró heterosis significativa. Nuestros resultados demuestran que las poblaciones amenazadas pueden beneficiarse de la introducción y del reforzamiento genético de individuos de poblaciones emparentadas. Las diferencias significativas entre las poblaciones artificiales en varios de los componentes de rendimiento medidos sugiere que la introducción o reforzamiento se logra mejor con material de una población local o, cuando no disponible, con material de varias poblaciones grandes. [source] Corporate-Governance Ratings and Company Performance: A Cross-European StudyCORPORATE GOVERNANCE, Issue 2 2010Annelies Renders ABSTRACT Manuscript Type: Empirical Research Question/Issue: Prior studies have failed to unequivocally establish a positive relationship between corporate-governance ratings and company performance, although theoretically, we would expect to find one. In this paper, we try to establish whether a positive relationship exists through modeling the relationship more carefully. Research Findings/Insights: After controlling for selection bias and endogeneity simultaneously, we find a significant positive relationship between corporate-governance ratings and performance. However, the strength of this relationship seems to depend on the quality of the institutional environment. Finally, we find that improvements in corporate-governance ratings over time result in decreasing marginal benefits in terms of performance. Theoretical/Academic Implications: Our paper contributes to the literature by showing that improved corporate-governance ratings lead to better performance, but that econometric problems might obscure this relationship. We also show that for a sample of developed countries the institutional environment affects the relationship between governance ratings and performance. Finally, this paper contributes to the literature on the impact, regarding compliance and effectiveness, of codes of good governance. Practitioner/Policy Implications: Our results are relevant for both companies and policy makers. They indicate that companies can improve performance by adhering to good corporate-governance practices. For policy makers, the findings suggest that soft laws and the invisible hand of the market lead to companies improving their corporate governance. [source] Where is Independent Director Efficacy?CORPORATE GOVERNANCE, Issue 4 2007Chin-Jung Luan Theoretically and empirically, the linkage between outside directors and firm performance is not conclusive in previous studies. We suspect that the mixed results are due to the failure to meet the requirements of the independence of outside directors. As the Taiwanese government has a rigorous definition of outside director independence, we employ a data set from Taiwan to test the impact of independent outside director assignment on a firm's performance. Our findings suggest that after controlling for a firm's past performance, independent outside director appointments do have a significantly positive impact on a firm's performance, and outperforming firms may have better performance but not significantly when assigning outside directors due to their absorptive capacity. [source] Supply Chain Strategy, Product Characteristics, and Performance Impact: Evidence from Chinese Manufacturers,DECISION SCIENCES, Issue 4 2009Yinan Qi ABSTRACT Supply chain management has become one of the most popular approaches to enhance the global competitiveness of business corporations today. Firms must have clear strategic thinking in order to effectively organize such complicated activities, resources, communications, and processes. An emerging body of literature offers a framework that identifies three kinds of supply chain strategies: lean strategy, agile strategy, and lean/agile strategy based on in-depth case studies. Extant research also suggests that supply chain strategies must be matched with product characteristics in order for firms to achieve better performance. This article investigates supply chain strategies and empirically tests the supply chain strategy model that posits lean, agile, and lean/agile approaches using data collected from 604 manufacturing firms in China. Cluster analyses of the data indicate that Chinese firms are adopting a variation of lean, agile, and lean/agile supply chain strategies identified in the western literature. However, the data reveal that some firms have a traditional strategy that does not emphasize either lean or agile principles. These firms perform worse than firms that have a strategy focused on lean, agile, or lean/agile supply chain. The strategies are examined with respect to product characteristics and financial and operational performance. The article makes significant contributions to the supply chain management literature by examining the supply chain strategies used by Chinese firms. In addition, this work empirically tests the applicability of supply chain strategy models that have not been rigorously tested empirically or in the fast-growing Chinese economy. [source] Comparison of Outcomes of Two Skills-teaching Methods on Lay-rescuers' Acquisition of Infant Basic Life Support SkillsACADEMIC EMERGENCY MEDICINE, Issue 9 2010Itai Shavit MD ACADEMIC EMERGENCY MEDICINE 2010; 17:979,986 © 2010 by the Society for Academic Emergency Medicine Abstract Objectives:, The objective was to determine if lay-rescuers' acquisition of infant basic life support (BLS) skills would be better when skills teaching consisted of videotaping practice and providing feedback on performances, compared to conventional skills-teaching and feedback methods. Methods:, This pilot-exploratory, single-blind, prospective, controlled, randomized study was conducted on November 12, 2007, at the Rappaport Faculty of Medicine, Technion,Israel Institute of Technology, Haifa, Israel. The population under study consisted of all first-year medical students enrolled in the 2007,2008 year. BLS training is part of their mandatory introductory course in emergency medicine. Twenty-three students with previous BLS training were excluded. The remaining 71 were randomized into four and then two groups, with final allocation to an intervention and control group of 18 and 16 students, respectively. All the students participated in infant BLS classroom teaching. Those in the intervention group practiced skills acquisition independently, and four were videotaped while practicing. Tapes were reviewed by the group and feedback was provided. Controls practiced using conventional teaching and feedback methods. After 3 hours, all subjects were videotaped performing an unassisted, lone-rescuer, infant BLS resuscitation scenario. A skills assessment tool was developed. It consisted of 25 checklist items, grouped into four sections: 6 points for "categories" (with specific actions in six categories), 14 points for "scoring" (of accuracy of performance of each action), 4 points for "sequence" (of actions within a category), and 1 point for "order" of resuscitation (complete and well-sequenced categories). Two blinded expert raters were given a workshop on the use of the scoring tool. They further refined it to increase scoring consistency. The main outcome of the study was defined as evidence of better skills acquisition in overall skills in the four sections and in the specific skills sets for actions in any individual category. Data analysis consisted of descriptive statistics. Results:, Means and mean percentages were greater in the intervention group in all four sections compared to controls: categories (5.72 [95.33%] and 4.69 [92.66%]), scoring (10.57 [75.50%] and 7.41 [43.59%]), sequence (2.28 [57.00%] and 1.66 [41.50%]), and order of resuscitation (0.96 [96.00%] and 0.19 [19.00%]). The means and mean percentages of the actions (skill sets) in the intervention group were also larger than those of controls in five out of six categories: assessing responsiveness (1.69 [84.50%] and 1.13 [56.50%]), breathing technique (1.69 [93.00%] and 1.13 [47.20%]), chest compression technique (3.19 [77.50%] and 1.84 [46.00%]), activating emergency medical services (EMS) (3.00 [100.00%] and 2.81 [84.50%]), and resuming cardiopulmonary resuscitation (0.97 [97.00%] and 0.47 [47.00%]). These results demonstrate better performance in the intervention group. Conclusions:, The use of videotaped practice and feedback for the acquisition of overall infant BLS skills and of specific skill sets is effective. Observation and participation in the feedback and assessment of nonexperts attempting infant BLS skills appeared to improve the ability of this group of students to perform the task. [source] Introduced plants of the invasive Solidago gigantea (Asteraceae) are larger and grow denser than conspecifics in the native rangeDIVERSITY AND DISTRIBUTIONS, Issue 1 2004Gabi Jakobs ABSTRACT Introduced plant species that became successful invaders appear often more vigorous and taller than their conspecifics in the native range. Reasons postulated to explain this better performance in the introduced range include more favourable environmental conditions and release from natural enemies and pathogens. According to the Evolution of Increased Competitive Ability hypothesis (EICA hypothesis) there is a trade-off between investment into defence against herbivores and pathogens, and investment into a stronger competitive ability. In this study, we conducted field surveys to investigate whether populations of the invasive perennial Solidago gigantea Ait (Asteraceae) differ with respect to growth and size in the native and introduced range, respectively. We assessed size and morphological variation of 46 populations in the native North American range and 45 populations in the introduced European range. Despite considerable variation between populations within continents, there were pronounced differences between continents. The average population size, density and total plant biomass were larger in European than in American populations. Climatic differences and latitude explained only a small proportion of the total variation between the two continents. The results show that introduced plants can be very distinct in their growth form and size from conspecifics in the native range. The apparently better performance of this invasive species in Europe may be the result of changed selection pressures, as implied by the EICA hypothesis. [source] The role of enemy release, tolerance and resistance in plant invasions: linking damage to performanceECOLOGY LETTERS, Issue 8 2010Young Jin Chun Ecology Letters (2010) 13: 937,946 Abstract An explanation for successful invasion is that invasive alien species sustain less pressure from natural enemies than co-occurring native species. Using meta-analysis, we examined whether invasive species: (1) incur less damage, (2) exhibit better performance in the presence of enemies, and (3) tolerate damage more than native species. Invasive alien species did not incur less damage than native species overall. The performance of invasive alien species was reduced compared to natives in the presence of enemies, indicating the invasive alien species were less tolerant to damage than native species. However, there was no overall difference in performance of invasive alien and native species with enemies present. The damage and degree of reduction in performance of invasive alien relative to native species did not depend on relatedness to natives. Our results suggest aliens may not always experience enemy release, and enemy release may not always result in greater plant performance. [source] Do Crises Induce Reform?ECONOMICS & POLITICS, Issue 2 2001Simple Empirical Tests of Conventional Wisdom We find evidence for the crisis-induces-reform hypothesis at extreme values of the inflation rate and the black market premium. Episodes of extremely high inflation or black market premiums are followed by periods of better performance than episodes of moderately high inflation or black market premiums. We fail to find similar evidence of the crisis hypothesis when crisis is measured as a high current account deficit, a high budget deficit, or a negative per capita growth rate. The pattern of foreign aid disbursements may help explain the results. Foreign aid is reduced at extreme values of inflation or the black market premium, while it is actually increased for more extreme values of the current account deficit and the budget deficit. [source] Recurrent neural networks with multi-branch structureELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 9 2008Takashi Yamashita Abstract Universal Learning Networks (ULNs) provide a generalized framework for many kinds of structures in neural networks with supervised learning. Multi-Branch Neural Networks (MBNNs) which use the framework of ULNs have already been shown to have better representation ability in feedforward neural networks (FNNs). The multi-branch structure of MBNNs can be easily extended to recurrent neural networks (RNNs) because the characteristics of ULNs include the connection of multiple branches with arbitrary time delays. In this paper, therefore, RNNs with multi-branch structure are proposed and are shown to have better representation ability than conventional RNNs. RNNs can represent dynamical systems and are useful for time series prediction. The performance evaluation of RNNs with multi-branch structure was carried out using a benchmark of time series prediction. Simulation results showed that RNNs with multi-branch structure could obtain better performance than conventional RNNs, and also showed that they could improve the representation ability even if they are smaller-sized networks. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 91(9): 37,44, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10157 [source] Characterization of voltage degradation in dynamic field gradient focusingELECTROPHORESIS, Issue 5 2008Jeffrey M. Burke Abstract Dynamic field gradient focusing (DFGF) is an equilibrium gradient method that utilizes an electric field gradient to simultaneously separate and concentrate charged analytes based on their individual electrophoretic mobilities. This work describes the use of a 2-D nonlinear, numerical simulation to examine the impact of voltage loss from the electrodes to the separation channel, termed voltage degradation, and distortions in the electric field on the performance of DFGF. One of the design parameters that has a large impact on the degree of voltage degradation is the placement of the electrodes in relation to the separation channel. The simulation shows that a distance of about 3,mm from the electrodes to the separation channel gives the electric field profile with least amount of voltage degradation. The simulation was also used to describe the elution of focused protein peaks. The simulation shows that elution under constant electric field gradient gives better performance than elution through shallowing of the electric field. Qualitative agreement between the numerical simulation and experimental results is shown. The simulation also illustrates that the presence of a defocusing region at the cathodic end of the separation channel causes peak dispersion during elution. The numerical model is then used to design a system that does not suffer from a defocusing region. Peaks eluted under this design experienced no band broadening in our simulations. Preliminary experimental results using the redesigned chamber are shown. [source] Partial regression method to fit a generalized additive modelENVIRONMETRICS, Issue 6 2007Shui He Abstract Generalized additive models (GAMs) have been used as a standard analytic tool in studies of air pollution and health during the last decade. The air pollution measure is usually assumed to be linearly related to the health indicator and the effects of other covariates are modeled through smooth functions. A major statistical concern is the appropriateness of fitting GAMs in the presence of concurvity. Generalized linear models (GLM) with natural cubic splines as smoothers (GLM,+,NS) have been shown to perform better than GAM with smoothing splines (GAM,+,S), in regard to the bias and variance estimates using standard model fitting methods. As nonparametric smoothers are attractive for their flexibility and easy implementation, search for alternative methods to fit GAM,+,S is warranted. In this article, we propose a method using partial residuals to fit GAM,+,S and call it the "partial regression" method. Simulation results indicate better performance of the proposed method compared to gam.exact function in S-plus, the standard tool in air pollution studies, in regard to bias and variance estimates. In addition, the proposed method is less sensitive to the degree of smoothing and accommodates asymmetric smoothers. Copyright © 2007 John Wiley & Sons, Ltd. [source] Conditioning Information and European Bond Fund PerformanceEUROPEAN FINANCIAL MANAGEMENT, Issue 2 2003Florinda Silva G11; G12; G14 In this paper we evaluate the performance of European bond funds using unconditional and conditional models. As conditioning information we use variables that we find to be useful in predicting bond returns in the European market. The results show that, in general, bond funds are not able to outperform passive strategies. These findings are robust to whatever model (unconditional versus conditional and single versus multi-index) we use. The multi-index model seems to add some explanatory power in relation to the single-index model. Furthermore, when we incorporate the predetermined information variables, we can observe a slight tendency towards better performance. This evidence is consistent with previous studies on stock funds and comes in support of the argument that conditional models might allow for a better assessment of performance. However, our results suggest that the impact of additional risk factors seems to be greater than the impact of incorporating predetermined information variables. [source] Performance and Policy of Foundation-owned Firms in GermanyEUROPEAN FINANCIAL MANAGEMENT, Issue 3 2002Markus Herrmann This paper compares performance and policy of foundation-owned firms and of listed corporations in Germany. Foundations have no owners so that there exist no individuals with financial ownership claims on firms which are wholly owned by foundations. This suggests weaker outside control of foundation-owned firms implying lower profitability. The empirical findings show a slightly better performance of foundation-owned firms compared to corporations. Foundation-owned firms display higher labour intensity, lower labour productivity, and lower salary levels. This policy promotes job security without endangering the viability of foundation-owned firms. [source] Warm Laser Shock Peening Driven Nanostructures and Their Effects on Fatigue Performance in Aluminum Alloy 6160,ADVANCED ENGINEERING MATERIALS, Issue 4 2010Chang Ye Warm laser shock peening is an innovative manufacturing process that integrates laser shock peening and dynamic aging to improve materials' fatigue performance. Compared to traditional laser shock peening (LSP), warm laser shock peening (WLSP) , i.e., LSP at elevated temperatures , provides better performance in many aspects. WLSP can induce nanoscale precipitation and high density dislocation arrangement, resulting in higher surface strength and lower surface roughness than LSP, which are both beneficial for fatigue life improvement. Due to pinning of the dislocation structure by nanoscale precipitates , so-called dislocation pinning effects , the relaxation of residual stress and surfaces dislocation arrangement is significantly reduced. In this study, AA6061 alloy is used to evaluate the WLSP process. It is found that the fatigue life improvements after WLSP are not only caused by large compressive residual stress and high density dislocations but also by the higher stability of the residual stresses and surface strength during cyclic loading. [source] The effect of arm crossing on persistence and performanceEUROPEAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 3 2008Ron Friedman Two experiments investigated the hypothesis that arm crossing serves as a proprioceptive cue for perseverance within achievement settings. Experiment 1 found that inducing participants to cross their arms led to greater persistence on an unsolvable anagram. Experiment 2 revealed that arm crossing led to better performance on solvable anagrams, and that this effect was mediated by greater persistence. No differences in comfort, instruction adherence, or mood were observed between the arms crossed and control conditions, and participants appeared to be unaware of the effect of arm crossing on their behavior. Implications of the findings are discussed in terms of the interplay between proprioceptive cues and contextual meaning. Copyright © 2007 John Wiley & Sons, Ltd. [source] Simple On-Line Scheduling Algorithms for All-Optical Broadcast-and-Select NetworksEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 1 2000Marco Ajmone Marsan This paper considers all-optical broadcast networks providing a number of slotted WDM channels for packet communications. Each network user is equipped with one tunable transmitter and one fixed receiver, so that full connectivity can be achieved by tuning transmitters to the different wavelengths. Tuning times are not negligible with respect to the slot time. A centralized network controller allocates slots in a TDWDM frame according to (long-term) bandwidth requests issued by users. Simple on-line transparent scheduling strategies are proposed, which accommodate bandwidth requests when they are received (on-line approach), with the constraint of not affecting existing allocations when a new request is served (transparency). Strategies that attempt to allocate in contiguous slots all the transmissions of each source on one wavelength reduce overheads, are simple, and provide good performance. Even better performance can be achieved, at the cost of a modest complexity increase, when the transparency constraint is not strictly imposed, i.e., when a full re-allocation of existing connections is performed once in a while. [source] Combining wavelet-based feature extractions with relevance vector machines for stock index forecastingEXPERT SYSTEMS, Issue 2 2008Shian-Chang Huang Abstract: The relevance vector machine (RVM) is a Bayesian version of the support vector machine, which with a sparse model representation has appeared to be a powerful tool for time-series forecasting. The RVM has demonstrated better performance over other methods such as neural networks or autoregressive integrated moving average based models. This study proposes a hybrid model that combines wavelet-based feature extractions with RVM models to forecast stock indices. The time series of explanatory variables are decomposed using some wavelet bases and the extracted time-scale features serve as inputs of an RVM to perform the non-parametric regression and forecasting. Compared with traditional forecasting models, our proposed method performs best. The root-mean-squared forecasting errors are significantly reduced. [source] A frequency-domain formulation of MCE method for multi-axial random loadingsFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 11 2008D. BENASCIUTTI ABSTRACT Many multi-axial fatigue limit criteria are formalized as a linear combination of a shear stress amplitude and a normal stress. To identify the shear stress amplitude, appropriate conventional definitions, as the minimum circumscribed circle (MCC) or ellipse (MCE) proposals, are in use. Despite computational improvements, deterministic algorithms implementing the MCC/MCE methods are exceptionally time-demanding when applied to "coiled" random loading paths resulting from in-service multi-axial loadings and they may also provide insufficiently robust and reliable results. It would be then preferable to characterize multi-axial random loadings by statistical re-formulations of the deterministic MCC/MCE methods. Following an early work of Pitoiset et al., this paper presents a statistical re-formulation for the MCE method. Numerical simulations are used to compare both statistical re-formulations with their deterministic counterparts. The observed general good trend, with some better performance of the statistical approach, confirms the validity, reliability and robustness of the proposed formulation. [source] Assessment of fire protection performance of water mist applied in exhaust ducts for semiconductor fabrication processFIRE AND MATERIALS, Issue 5 2005Yi-Liang Shu Abstract Fume exhaust pipes used in semiconductor facilities underwent a series of fire tests to evaluate the performance of a water mist system. The parameters considered were the amount of water that the mist nozzles used, the air flow velocity, the fire intensity and the water mist system operating pressure. In order to make a performance comparison, tests were also performed with a standard sprinkler system. The base case served as a reference and applied a single water mist nozzle (100 bar operating pressure, 7.3 l/min water volume flux and 200 µm mean droplet size) installed in the pipe (60 cm in diameter) subjected to a 350°C air flow with an average velocity of 2 m/s. In such a case, the temperature in the hot flow dropped sharply as the water mist nozzle was activated and reached a 60°C saturation point. Under the same operating conditions, four mist nozzles were applied, and made no further contribution to reducing the fire temperature compared with the case using only a single nozzle. Similar fire protection performances to that in the base case were still retained when the exhaust flow velocity increased to 3 m/s and the inlet air temperature was increased to 500°C due to a stronger input fire scenario, respectively. Changing to a water mist system produced a better performance than a standard sprinkler. With regard to the effect of operating pressure of water mist system, a higher operating pressure can have a better performance. The results above indicate that the droplet size in a water-related fire protection system plays a critical role. Copyright © 2005 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||