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81.
82.
An engagement mode involves a subject (e.g., a user of information technology, or IT) who is engaged in an activity with an object in a certain manner (the mode). The purpose of this study is to develop a general model of engagement modes that may be used for understanding how IT-related activities are shaped by properties of the user and the IT object. A questionnaire involving items on IT engagement and the experience of flow was administered to 300 participants. The results supported an engagement mode (EM) model involving 5 different engagement modes (enjoying/acceptance, ambition/curiosity, avoidance/hesitation, frustration/ anxiety, and efficiency/productivity) characterized on 3 dimensions (evaluation of object, locus of control between subject and object, and intrinsic or extrinsic focus of motivation). The flow experience follows from a balance between enjoying/ acceptance and efficiency/productivity propelled by ambition/curiosity. The EM model could provide a platform for considering how IT users, IT applications, and IT environments should work together to yield both enjoyment and efficiency. Actual or potential applications of this research include designing IT training programs on different levels of specificity. 相似文献
83.
Rohrlack T Christoffersen K Hansen PE Zhang W Czarnecki O Henning M Fastner J Erhard M Neilan BA Kaebernick M 《Journal of chemical ecology》2003,29(8):1757-1770
This paper describes the purification and characterization of microviridin J, a newly discovered metabolite of Microcystis that causes a lethal molting disruption in Daphnia spp., upon ingestion of living cyanobacterial cells. Microviridin J consists of an acetylated chain of 13 amino acids arranged in three rings and two side chains. Unlike other known isoforms of microviridin, microviridin J contains arginine that imparts a unique solution conformation characterized by proximal hydrophobic interactions between Arg and other regions of the molecule. This eventually results in the formation and stabilization of an additional ring system. Microviridin J potently inhibits porcine trypsin, bovine chymotrypsin, and daphnid trypsin-like proteases. The activity against trypsin is most likely due to Arg and its distinctive conformational interactions. Overall, the data presented for microviridin J emphasize once again the ability of cyanobacteria to produce numerous and potent environmental toxins. 相似文献
84.
Genes controlling ovulation rate in sheep 总被引:4,自引:0,他引:4
Montgomery GW Galloway SM Davis GH McNatty KP 《Reproduction (Cambridge, England)》2001,121(6):843-852
Sheep provide a valuable model for studying the genetic control of ovulation rate. Recent progress includes the identification of mutations in BMP15 (bone morphogenetic protein 15) that increase ovulation rate in heterozygous carriers and block follicular development in homozygous carriers. The genes characterized to date appear to act principally within the ovary and result in earlier maturity of granulosa cells and reduced follicular size. There may also be other sites of action, and increased FSH concentrations appear to be important in the expression of the FecB phenotype. A new locus on the X chromosome in New Zealand Coopworth sheep increases ovulation rate by about 0.4 and is maternally imprinted. Results from studies in the Cambridge and Belclare breeds indicate that further genes remain to be characterized. Finding the first mutations leading directly to variation in ovulation rate is likely to speed up the identification and molecular analysis of these other genes. There is still much to learn about follicular development and the control of litter size from genetic models in sheep. 相似文献
85.
Alexandros Kalousis Julien Prados Melanie Hilario 《Knowledge and Information Systems》2007,12(1):95-116
With the proliferation of extremely high-dimensional data, feature selection algorithms have become indispensable components
of the learning process. Strangely, despite extensive work on the stability of learning algorithms, the stability of feature
selection algorithms has been relatively neglected. This study is an attempt to fill that gap by quantifying the sensitivity
of feature selection algorithms to variations in the training set. We assess the stability of feature selection algorithms
based on the stability of the feature preferences that they express in the form of weights-scores, ranks, or a selected feature
subset. We examine a number of measures to quantify the stability of feature preferences and propose an empirical way to estimate
them. We perform a series of experiments with several feature selection algorithms on a set of proteomics datasets. The experiments
allow us to explore the merits of each stability measure and create stability profiles of the feature selection algorithms.
Finally, we show how stability profiles can support the choice of a feature selection algorithm.
Alexandros Kalousis received the B.Sc. degree in computer science, in 1994, and the M.Sc. degree in advanced information systems, in 1997, both
from the University of Athens, Greece. He received the Ph.D. degree in meta-learning for classification algorithm selection
from the University of Geneva, Department of Computer Science, Geneva, in 2002. Since then he is a Senior Researcher in the
same university. His research interests include relational learning with kernels and distances, stability of feature selection
algorithms, and feature extraction from spectral data.
Julien Prados is a Ph.D. student at the University of Geneva, Switzerland. In 1999 and 2001, he received the B.Sc. and M.Sc. degrees in
computer science from the University Joseph Fourier (Grenoble, France). After a year of work in industry, he joined the Geneva
Artificial Intelligence Laboratory, where he is working on bioinformatics and datamining tools for mass spectrometry data
analysis.
Melanie Hilario has a Ph.D. in computer science from the University of Paris VI and currently works at the University of Geneva’s Artificial
Intelligence Laboratory. She has initiated and participated in several European research projects on neuro-symbolic integration,
meta-learning, and biological text mining. She has served on the program committees of many conferences and workshops in machine
learning, data mining, and artificial intelligence. She is currently an Associate Editor of theInternational Journal on Artificial Intelligence Toolsand a member of the Editorial Board of theIntelligent Data Analysis journal. 相似文献
86.
Miniaturization of Electrostatic Fluid Accelerators 总被引:1,自引:0,他引:1
Chih-Peng Hsu Jewell-Larsen N.E. Krichtafovitch I.A. Montgomery S.W. Dibene J.T. Mamishev A.V. 《Journal of microelectromechanical systems》2007,16(4):809-815
Existing thermal-management methods for electronics do not meet the technology needs and remain a major bottleneck in the evolution of computing, sensing, and information technology. The decreasing size of microelectronic components and the resulting increasing thermal output density require novel cooling solutions. Electrostatic fluid accelerators (EFAs), also known as electrohydrodynamic ionic wind pumps, have the potential of becoming a critical element of electronic thermal-management solutions. In order to take full advantage of EFA-based thermal management, it is essential to miniaturize EFA technology. This paper demonstrates the successful operation of a mesoscale microfabricated silicon EFA. Several cantilever structures fabricated in bulk silicon with radii of tip curvature ranging from 0.5 to 25 mum are used as the corona electrode. The device was fabricated using the combination of deep reactive ion etching (DRIE) and reactive ion etch (RIE) microfabrication processes. Forced convection cooling is demonstrated using infrared imaging, showing a 25degC surface temperature reduction over an actively heated substrate. The fabrication and test results of a mesoscale microfabricated EFA are presented in this paper. 相似文献
87.
McKay Kevin M.; Hill Melanie S.; Freedman Suzanne R.; Enright Robert D. 《Canadian Metallurgical Quarterly》2007,44(1):14
In recent years Enright and Fitzgibbon's (2000) process model of forgiveness therapy has received substantial theoretical and empirical attention. However, both the process model of forgiveness therapy and the social-cognitive developmental model on which it is based have received criticism from feminist theorists. The current paper considers feminist criticisms of forgiveness therapy and uses a feminist lens to identify potential areas for growth. Specifically, Worell and Remer's (2003) model of synthesizing feminist ideals into existing theory was consulted, areas of bias within the forgiveness model of psychotherapy were identified, and strategies for restructuring areas of potential bias were introduced. Further, the authors consider unique aspects of forgiveness therapy that can potentially strengthen existing models of feminist therapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
88.
Zinc supplementation induces regulatory T cells by inhibition of Sirt‐1 deacetylase in mixed lymphocyte cultures 下载免费PDF全文
89.
Auffan M Decome L Rose J Orsiere T De Meo M Briois V Chaneac C Olivi L Berge-Lefranc JL Botta A Wiesner MR Bottero JY 《Environmental science & technology》2006,40(14):4367-4373
Although the current production of oxide nanoparticles may be modest, the wide range of proposed applications and forecasted growth in production has raised questions about the potential impact of these nanoparticles on the environment and human health. Iron oxide nanoparticles have been proposed for an increasing number of biomedical applications although in vitro toxicity depending on the particles coating has been evidenced. The aim of this study was to examine the potential in vitro cyto- and genotoxicity on human dermal fibroblasts of DMSA-coated maghemite nanoparticles (NmDMSA) as a function of well-defined physicochemical states. Well-stabilized NmDMSA produced weak cytotoxic and no genotoxic effects. This is attributed in part to the DMSA coating, which serves as a barrier for a direct contact between nano-oxide and fibroblasts, inhibiting a potential toxic effect. 相似文献
90.
R. Winkler E. R. Woolliams W. S. Hartree S. G. R. Salim N. P. Fox J. R. Mountford Malcolm White S. R. Montgomery 《International Journal of Thermophysics》2007,28(6):2087-2097
For accurate determinations of thermodynamic temperature, NPL has developed its absolute radiation thermometer (ART), which
is calibrated traceably against a cryogenic radiometer. This article reviews some of the potential sources of systematic uncertainty
present in the calibration and use of ART. In particular, this article is concerned with the evaluation of the size-of-source
effect and the lens transmittance, as well as potential differences in the responsivity of a transfer trap detector when calibrated
in terms of radiant power and used in irradiance mode. 相似文献