CiteULike: Tag paper

Cranial implant design using augmented reality immersive system.

Z Ai — 2008-02-14T17:38:00-00:00

Stud Health Technol Inform, Vol. 125 (2007), pp. 7-12.

Software tools that utilize haptics for sculpting precise fitting cranial implants are utilized in an augmented reality immersive system to create a virtual working environment for the modelers. The virtual environment is designed to mimic the traditional working environment as closely as possible, providing more functionality for the users. The implant design process uses patient CT data of a defective area. This volumetric data is displayed in an implant modeling tele-immersive augmented reality system where the modeler can build a patient specific implant that precisely fits the defect. To mimic the traditional sculpting workspace, the implant modeling augmented reality system includes stereo vision, viewer centered perspective, sense of touch, and collaboration. To achieve optimized performance, this system includes a dual-processor PC, fast volume rendering with three-dimensional texture mapping, the fast haptic rendering algorithm, and a multi-threading architecture. The system replaces the expensive and time consuming traditional sculpting steps such as physical sculpting, mold making, and defect stereolithography. This augmented reality system is part of a comprehensive tele-immersive system that includes a conference-room-sized system for tele-immersive small group consultation and an inexpensive, easily deployable networked desktop virtual reality system for surgical consultation, evaluation and collaboration. This system has been used to design patient-specific cranial implants with precise fit.

Visualization of large-scale confocal data using computer cluster.

B Jin — 2008-02-14T17:37:25-00:00

Stud Health Technol Inform, Vol. 125 (2007), pp. 206-208.

A virtual reality system with remote computer cluster for interactive three-dimensional reconstruction and alignment of large confocal microscopy data is presented. It provides the flexibility and the accumulated power of computer cluster for this specific application.

Comparing vasculogenic mimicry with endothelial cell-lined vessels: techniques for 3D reconstruction and quantitative analysis of tissue components from archival paraffin blocks.

AY Lin — 2008-02-14T17:36:05-00:00

Appl Immunohistochem Mol Morphol, Vol. 15, No. 1. (March 2007), pp. 113-119.

We previously described techniques to generate 3-dimensional reconstructions of the tumor microcirculation using immunofluorescence histochemistry and laser scanning confocal microscopy on serial sections from archival formalin-fixed, paraffin-embedded tissues. By aligning sequential z-stacks in an immersive visualization environment (ImmersaDesk), the need to insert fiduciary markers into tissue was eliminated. In this study, we developed methods to stitch overlapping confocal z-series together to extend the surface area of interest well beyond that captured by the confocal microscope objective and developed methods to quantify the distribution of markers of interest in 3 dimensions. These techniques were applied to the problem of comparing the surface area of nonendothelial cell-lined, laminin-rich looping vasculogenic mimicry (VM) patterns that are known to transmit fluid, with the surface area of endothelial cell-lined vessels in metastatic uveal melanoma to the liver in 3 dimensions. After labeling sections with antibodies to CD34 and laminin, the surface area of VM patterns to vessels was calculated by segmenting out structures that labeled with laminin but not with CD34 from those structures labeling with CD34, or CD34 and laminin. In metastatic uveal melanoma tissues featuring colocalization of high microvascular density [66.4 microvessels adjusted for 0.313 mm2 area (range 56.7 to 72.7)] and VM patterning, the surface area of VM patterns was 11.6-fold greater (range 10.8 to 14.1) than the surface provided by CD34-positive vessels. These methods may be extended to visualize and quantify molecular markers in 3 dimensions in a variety of pathologic entities from archival paraffin-embedded tissues.

Modeling the behavior of uveal melanoma in the liver.

R Folberg — 2008-02-14T17:31:10-00:00

Invest Ophthalmol Vis Sci, Vol. 48, No. 7. (July 2007), pp. 2967-2974.

PURPOSE: To model the behavior of uveal melanoma in the liver. METHODS: A 15-muL suspension of metastatic MUM2B or either primary OCM1 or M619 uveal melanoma cells was injected into the liver parenchyma of 105 CB17 SCID mice through a 1-cm abdominal incision. Animals were killed at 2, 4, 6, or 8 weeks after injection. Before euthanatization, 3% FITC-BSA buffer was injected into the retro-orbital plexus of one eye of three mice. Liver tissues were examined by light and fluorescence microscopy, and were stained with human anti-laminin. Vasculogenic mimicry patterns were reconstructed from serial laser scanning confocal microscopic stacks. RESULTS: OCM1a cells formed microscopic nodules in the mouse liver within 2 weeks after injection and metastasized to the lung 6 weeks later. By contrast, M619 and MUM2B cells formed expansile nodules in the liver within 2 weeks and gave rise to pulmonary metastases within 4 weeks after injection. Vasculogenic mimicry patterns, composed of human laminin and identical with those in human primary and metastatic uveal melanomas, were detected in the animal model. The detection of human rather than mouse laminin in the vasculogenic mimicry patterns in this model demonstrates that these patterns were of tumor cell origin and were not co-opted from the mouse liver microenvironment. CONCLUSIONS: There are currently no effective treatments for metastatic uveal melanoma. This direct-injection model focuses on critical interactions between the tumor cell and the liver. It provides for translationally relevant approaches to the development of new modalities to detect small tumor burdens in patients, to study the biology of clinical dormancy of metastatic disease in uveal melanoma, to design and test novel treatments to prevent the emergence of clinically manifest liver metastases after dormancy, and to treat established uveal melanoma metastases.

Systematic Identification of mRNAs Recruited to Argonaute 2 by Specific microRNAs and Corresponding Changes in Transcript Abundance.

DG Hendrickson — 2008-05-08T19:09:14-00:00

PLoS ONE, Vol. 3, No. 5. (2008)

microRNAs (miRNAs) are small non-coding RNAs that regulate mRNA stability and translation through the action of the RNAi-induced silencing complex (RISC). Our current understanding of miRNA function is inferred largely from studies of the effects of miRNAs on steady-state mRNA levels and from seed match conservation and context in putative targets. Here we have taken a more direct approach to these issues by comprehensively assessing the miRNAs and mRNAs that are physically associated with Argonaute 2 (Ago2), which is a core RISC component. We transfected HEK293T cells with epitope-tagged Ago2, immunopurified Ago2 together with any associated miRNAs and mRNAs, and quantitatively determined the levels of these RNAs by microarray analyses. We found that Ago2 immunopurified samples contained a representative repertoire of the cell's miRNAs and a select subset of the cell's total mRNAs. Transfection of the miRNAs miR-1 and miR-124 caused significant changes in the association of scores of mRNAs with Ago2. The mRNAs whose association with Ago2 increased upon miRNA expression were much more likely to contain specific miRNA seed matches and to have their overall mRNA levels decrease in response to the miRNA transfection than expected by chance. Hundreds of mRNAs were recruited to Ago2 by each miRNA via seed sequences in 3'-untranslated regions and coding sequences and a few mRNAs appear to be targeted via seed sequences in 5'-untranslated regions. Microarray analysis of Ago2 immunopurified samples provides a simple, direct method for experimentally identifying the targets of miRNAs and for elucidating roles of miRNAs in cellular regulation.

Paper windows: interaction techniques for digital paper

David Holman — 2008-06-12T19:20:06-00:00

(2005), pp. 591-599.

Genome sequence of the nematode C. elegans: a platform for investigating biology.

2005-05-09T20:21:07-00:00

Science, Vol. 282, No. 5396. (11 December 1998), pp. 2012-2018.

The 97-megabase genomic sequence of the nematode Caenorhabditis elegans reveals over 19,000 genes. More than 40 percent of the predicted protein products find significant matches in other organisms. There is a variety of repeated sequences, both local and dispersed. The distinctive distribution of some repeats and highly conserved genes provides evidence for a regional organization of the chromosomes.

A Developmental Perspective on Standardized Achievement Testing

Scott Paris — 2008-05-08T16:53:43-00:00

EDUCATIONAL RESEARCHER, Vol. 20, No. 5. (1 June 1991), pp. 12-20.

Throughout the 1980s there was a proliferation of achievement testing in America to promote and assure the effectiveness of educational reforms. However, both traditional innovative forms of assessment failed to consider the cumulative impact of repeated testing on students" attitudes and motivation. Our surveys of students in Grades 2-11 revealed that by adolescence many students become suspicious and cynical about tests. A large number of students, especially low achievers, become anxious about tests, cheat, try half-heartedly, or use poor test-taking strategies. These reactions may preserve students' feeling of competence when they receive low test scores, but they undermine the validity of the test scores and discourage genuine learning. A developmental perspective on testing may prevent students' counterproductive reactions and may help to guide reforms in educational assessment. 10.3102/0013189X020005012

Infection related renal impairment: a major cause of acute allograft dysfunction.

MR Nampoory — 2006-08-21T13:38:07-00:00

Exp Clin Transplant, Vol. 1, No. 1. (June 2003), pp. 60-64.

We prospectively analyzed the impact of post-transplant infections on the renal function in 532 stable renal transplant recipients (M=340; F=192) over a period of 5 years. Their age ranged from 3-75 years (40+14 years). During the follow-up period, 52 patients expired and 64 lost on followup. We defined renal impairment (RI) as a persistent rise in serum creatinine above 20% from baseline value. 495 episodes of RI occurred in 269 recipients. This included 180-36% episodes of acute rejection, 53-10.7% Cyclosporine toxicity, 236-47.7% infection related renal impairment [IRRI] and 26-5.3% others. The severity of renal failure is less in IRRI (100+90.2) than that of acute rejection (166+127.1), but was more than that in cyclosporine toxicity (50+42.2). Sites of infection in IRRI were urinary (33%), respiratory (26.3%), septicemia (15.7%) and others (25.4%). Episode of IRRI occurred more frequently in LURD (159-67.4%) compared to LRD-RTR (50-21.2%). Occurrence of IRRI is more significantly higher in patients on triple drug immunosuppression (IS) (34.3%) than those on two drug IS (13.2%) (P=or<0.01). Ecoli (23.1%), Pseudomonas (11.1%), Salmonella (8.8%), Klebsiella (8.8%) and Staphylococai (8.3%) were the major organisms producing IRRI. IRRI is frequent (27.8%) during the first six months. Present study denotes that IRRI is a major cause of acute failure in RTR.

Some Guidelines on Technical Writing

James Wilson — 2007-11-14T19:03:14-00:00

s (National Information Standards Organization 1997), pages 91--93 of Carter (1987), page 5 of the AIP Style Manual (American Institute of Physics 1990), or chapter 6 of Day (1994). B. Write the rest of the paper as though you were talking to a group of interested colleagues about your work. 1. Strive for accuracy and clarity above all else. 2. In constructing each sentence, place old and new information in the respective positions where readers generally expect to find these types of...

Semantic Wikipedia

Max V&\#246;lkel — 2006-09-25T12:11:43-00:00

(2006), pp. 585-594.

Automated building generalization based on urban morphology and Gestalt theory

Z Li — 2008-06-04T14:34:44-00:00

International Journal of Geographical Information Science, Vol. 18, No. 5. (2004), pp. 513-534.

Building generalization is a difficult operation due to the complexity of the spatial distribution of buildings and for reasons of spatial recognition. In this study, building generalization is decomposed into two steps, i.e. building grouping and generalization execution. The neighbourhood model in urban morphology provides global constraints for guiding the global partitioning of building sets on the whole map by means of roads and rivers, by which enclaves, blocks, superblocks or neighbourhoods are formed; whereas the local constraints from Gestalt principles provide criteria for the further grouping of enclaves, blocks, superblocks and/or neighbourhoods. In the grouping process, graph theory, Delaunay triangulation and the Voronoi diagram are employed as supporting techniques. After grouping, some useful information, such as the sum of the building's area, the mean separation and the standard deviation of the separation of buildings, is attached to each group. By means of the attached information, an appropriate operation is selected to generalize the corresponding groups. Indeed, the methodology described brings together a number of well-developed theories/techniques, including graph theory, Delaunay triangulation, the Voronoi diagram, urban morphology and Gestalt theory, in such a way that multiscale products can be derived.

A new approach to subdivision simplification

Marc de Berg — 2008-06-04T14:42:07-00:00

Vol. 4 (1995), pp. 79-88.

The line simplification problem is an old and well-studied problem in cartography. Although there are several algorithms to compute a simplification, there seem to be no algorithms that perform line simplification in the context of other geographical objects. This paper presents a nearly quadratic time algorithm for the following line simplification problem: Given a polygonal line, a set of extra points, and a real ffl ? 0, compute a simplification that guarantees (i) a maximum error ffl, (ii)...

How should pathogen transmission be modelled?

Hamish Mccallum — 2008-07-11T19:08:16-00:00

Trends in Ecology & Evolution, Vol. 16, No. 6. (1 June 2001), pp. 295-300.

Host-pathogen models are essential for designing strategies for managing disease threats to humans, wild animals and domestic animals. The behaviour of these models is greatly affected by the way in which transmission between infected and susceptible hosts is modelled. Since host-pathogen models were first developed at the beginning of the 20th century, the [`]mass action' assumption has almost always been used for transmission. Recently, however, it has been suggested that mass action has often been modelled wrongly. Alternative models of transmission are beginning to appear, as are empirical tests of transmission dynamics.

The character, value, and management of personal paper archives

Steve Whittaker — 2005-05-03T00:34:02-00:00

ACM Trans. Comput.-Hum. Interact., Vol. 8, No. 2. (June 2001), pp. 150-170.

Environmental Reform in the Electricity Sector: China and India

Antonette D'Sa — 2008-03-29T22:06:31-00:00

The Journal of Environment Development, Vol. 15, No. 2. (1 June 2006), pp. 158-183.

This article analyzes the challenges to effective environmental protection in the power sectors of China and India. Its analytical framework consists of identification of environmental policies and regulations affecting electricity generation, assessment of problems faced when implementing these policies and regulations, and finally recommendations for surmounting the barriers encountered. Environmental issues in the electricity sector have been addressed directly, through laws and governmental orders, and indirectly, through policies on alternative technologies and efficiency improvement. However, successful environmental regulation has been hampered in these large developing countries by the compelling need for energy and the consequent rapid increase in electricity generation. Solutions to these problems lie in combinations of cleaner and more-efficient generation, appropriate control equipment, and more-efficient end-use devices. Among factors that facilitate effective adoption of these solutions are state prioritization, fiscal and financial incentives, appropriate technological choices, institutional involvement, integrated planning, public participation, and international commitments. 10.1177/1070496506288222

Familial and psychological correlates of smoking in black and white adolescents.

EH Johnson — 2006-08-16T22:48:12-00:00

Ethn Dis, Vol. 1, No. 4. (1991), pp. 320-334.

Cigarette smoking is considered to be the single most preventable contributor to chronic diseases, but there is still great controversy about the initiation and maintenance of smoking among adolescents. The goal of this study was to examine familial and psychological factors that contribute to the initiation and maintenance of smoking among black and white adolescents. To accomplish this, we tested 602 male (275 black and 327 white) and 460 female (174 black and 286 white) adolescent students enrolled in health classes in Tampa, Florida. Among blacks, 15.6% were currently smoking cigarettes, compared to 34.8% of the white students. Blacks who initiated smoking were most influenced by having a sister who smoked, while maintenance was most influenced by an older brother who smoked. In contrast, white adolescents who initiated smoking were more likely to have an older brother who smoked, while maintenance of smoking was predicted by having a father who smoked. Furthermore, the data show that both the initiation and the maintenance of smoking among blacks is related to the experience of intense feelings of anger and irritability, while among white adolescents, these emotions contribute only to the initiation of smoking. These data indicate that smokers and nonsmokers differ in their emotional reactions to stress, and that ethnicity (black vs white) is an important determinant in the association between smoking and emotional reactions to stress. The overall pattern of the findings in this inquiry suggests that the efficacy of antismoking treatment procedures could be enhanced by targeting exaggerated emotional reactions for modification. The data also suggest that smoking prevention programs for adolescents should take into consideration pressures to smoke that may arise from having family members who smoke. Given the inherent problems of a cross-sectional research design, future research is needed to clarify the interrelationships between smoking, ethnicity, and measures of the experience and expression of anger.

Angular spectrum method with correction of anamorphism for numerical reconstruction of digital holograms on tilted planes

S de Nicola — 2006-10-17T14:02:21-00:00

Optics Express, Vol. 13 (November 2005), 9935.

We present a new method for numerically reconstructing digital holograms on tilted planes. The method is based on the angular spectrum of plane waves. Fast Fourier transform algorithm is used twice and coordinate rotation in the Fourier domain enables to reconstruct the object field on the tilted planes. Correction of the anamorphism resulting from the coordinate transformation is performed by suitable interpolation of the spectral data. Experimental results are presented to demonstrate the method for a singleaxis rotation. The algorithm is especially useful for tomographic image reconstruction.

Prediction of ultrasonic field propagation through layered media using the extended angular spectrum method.

CJ Vecchio — 2006-10-17T13:39:26-00:00

Ultrasound Med Biol, Vol. 20, No. 7. (1994), pp. 611-622.

The angular spectrum method is a powerful technique for modeling the propagation of acoustic fields. The technique can predict an acoustic pressure field distribution over a plane, based upon knowledge of the pressure field distribution at a parallel plane. Predictions in both the forward and backward propagation directions are possible. In addition to predicting the effects of diffraction, the model also includes the effects of attenuation, refraction, dispersion, phase distortion, and the effects of finite amplitude acoustic propagation. No other model currently exists which can predict the propagation of wideband acoustic fields produced by sources of arbitrary geometry including all of the above propagation effects. Prior investigations have focused on using backward propagation predictions to analyze the surface vibration patterns of acoustic radiators. In contrast, the current effort has placed particular emphasis on verifying the model in the forward propagation case. In this paper, both forward and backward predictions are presented which demonstrate the ability of the model to characterize a three-dimensional acoustic field based upon measurements at a single plane. Results are also presented which examine the ability of the extended model to predict acoustic propagation through media composed of stacked homogeneous layers. The model has immediate applications in the study of acoustic phenomena and in the field of acoustic transducer design. Additionally, significant progress has been made toward the ultimate goal of predicting the degradation of acoustic transducer performance due to propagation through inhomogeneous, nonlinear, tissue-like media.

IN THIS ISSUE

2008-06-03T21:21:24-00:00

J. Natl. Cancer Inst., Vol. 100, No. 11. (4 June 2008), 755.

10.1093/jnci/djn182

Lapicque's introduction of the integrate-and-fire model neuron (1907)

LF Abbott — 2008-06-29T00:43:58-00:00

Brain Research Bulletin, Vol. 50, No. 5-6. ( 1999), pp. 303-304.

Structural design under bounded uncertainty--Optimization with anti-optimization

I Elishakoff — 2006-04-16T17:51:43-00:00

Computers & Structures, Vol. 53, No. 6. (17 December 1994), pp. 1401-1405.

In many cases precise probabilistic data are not available on uncertainty in loads, but the magnitude of the uncertainty can be bound. This paper proposes a design approach for structural optimization with uncertain but bounded loads. The problem of identifying critical loads is formulated mathematically as an optimization problem in itself (called anti-optimization), so that the design problem is formulated as a two-level optimization. For linear structural analysis it is shown that the antioptimization part is limited to consideration of the vertices of the load-uncertainty domain. An example of a ten-bar truss is used to demonstrate that we cannot replace the anti-optimization process by considering the largest possible loads.

Effect of Environmental Dynamism on Relational Governance in Manufacturer-Supplier Relationships: A Contingency Framework and an Empirical Test

Ashwin Joshi — 2008-01-30T22:45:51-00:00

Journal of the Academy of Marketing Science, Vol. 31, No. 2. (1 April 2003), pp. 176-188.

The effect of dynamism in the downstream (i.e., customer and competitive) environment on the manner in which manufacturers manage their upstream (i.e., supplier) relationships is not well understood in the literature. While some prior studies suggest that manufacturers will adopt relational governance with suppliers in response to dynamism in the downstream environment, other studies suggest that manufacturers will avoid relational governance with suppliers when faced with environmental dynamism. Drawing from the literature on interparty learning, the authors develop a conceptual framework wherein the validating conditions for each conclusion are identified. Results from a survey of 221 manufacturing organizations show that in dynamic environments, manufacturers adopt (avoid) relational governance with suppliers under two conditions: (1) when manufacturer collaborative belief is high (low) and (2) when supplier knowledge is high (low). The results are discussed in terms of their managerial and future research implications. 10.1177/0092070302250901

Fracture in mesoscopic disordered systems

MEJ Karttunen — 2007-12-20T20:17:44-00:00

Physical Review B, Vol. 49, No. 14. (1 April 1994), 9453.

A simple mechanical model of planar fibrous materials with mesoscopic disorder is introduced and analyzed. In this scalar model a shear modulus controls the stress transfer in the transverse direction. The system is studied using the effective medium approximation and computer simulations; the comparison between them is quite favorable. In the disorder-controlled regime the stress-strain relation; the number of broken cells at the onset of crack propagation; and the length of the final crack scale with the system size as L 2 ; L 1.7 ; and L ; respectively. The mechanical properties are controlled by the interplay between disorder and shear modulus; which is studied in detail.

Electrophysiological measures of time processing in infant and adult brains: Weber's Law holds.

EM Brannon — 2008-02-27T18:44:50-00:00

J Cogn Neurosci, Vol. 20, No. 2. (February 2008), pp. 193-203.

Behavioral studies have demonstrated that time perception in adults, children, and nonhuman animals is subject to Weber's Law. More specifically, as with discriminations of other features, it has been found that it is the ratio between two durations rather than their absolute difference that controls the ability of an animal to discriminate them. Here, we show that scalp-recorded event-related electrical brain potentials (ERPs) in both adults and 10-month-old human infants, in response to changes in interstimulus interval (ISI), appear to obey the scalar property found in time perception in adults, children, and nonhuman animals. Using a timing-interval oddball paradigm, we tested adults and infants in conditions where the ratio between the standard and deviant interval in a train of homogeneous auditory stimuli varied such that there was a 1:4 (only for the infants), 1:3, 1:2, and 2:3 ratio between the standard and deviant intervals. We found that the amplitude of the deviant-triggered mismatch negativity ERP component (deviant-ISI ERP minus standard-ISI ERP) varied as a function of the ratio of the standard to deviant interval. Moreover, when absolute values were varied and ratio was held constant, the mismatch negativity did not vary.

Awareness of action: Inference and prediction

James Moore — 2008-03-22T05:45:19-00:00

Consciousness and Cognition, Vol. 17, No. 1. (March 2008), pp. 136-144.

This study investigates whether the conscious awareness of action is based on predictive motor control processes, or on inferential "sense-making" process that occur after the action itself. We investigated whether the temporal binding between perceptual estimates of operant actions and their effects depends on the occurrence of the effect (inferential processes) or on the prediction that the effect will occur (predictive processes). By varying the probability with which a simple manual action produced an auditory effect, we showed that both the actual and the predicted occurrence of the effect played a role. When predictability of the effect of action was low, temporal binding was found only on those trials where the auditory effect occurred. In contrast, when predictability of the effect of action was high, temporal binding occurred even on trials where the action produced no effect. Further analysis showed that the predictive process is modulated by recent experience of the action-effect relation. We conclude that the experience of action depends on a dynamic combination of predictive and inferential processes.

Event-related potentials dissociate facilitation and interference effects in the numerical Stroop paradigm

Dénes Szucs — 2008-04-18T10:01:17-00:00

Neuropsychologia, Vol. 45, No. 14. (2007), pp. 3190-3202.

In the numerical Stroop paradigm (NSP) participants compare simultaneously presented Arabic digits based on either their numerical or on their physical size dimension. Responses are faster when the numerical and size dimensions are congruent with each other (facilitation), and responses are slower when the numerical and size dimensions are incongruent with each other (interference). We aimed to find out whether facilitation and interference appears during the course of perceptual or response processing. To this end, facilitation and interference effects in the amplitude of event-related brain potentials (ERPs) were examined. The onset of motor preparation was determined by monitoring the lateralized readiness potential. In numerical comparison one facilitation effect was related to perceptual processing at the level of the magnitude representation. A second facilitation effect and interference effects appeared during response processing. In size comparison facilitation and interference appeared exclusively during response processing. In both tasks, ERP interference effects were probably related to contextual analysis and to the conflict monitoring and selection for action activity of the anterior cingulate cortex. The results demonstrate that facilitation and interference effects in the NSP appear during multiple stages of processing, and that they are related to different cognitive processes. Therefore these effects should be clearly separated in studies of the NSP. A model of the processes involved in the NSP is provided and implications for studies of the NSP are drawn.

Effects of response sequence length on motor programming: A chronometric analysis

Hannes Schröter — 2008-04-19T21:21:23-00:00

Acta Psychologica, Vol. 128, No. 1. (May 2008), pp. 186-196.

The present experiment studied choice response context effects on the programming of response sequences using behavioural and electrophysiological methods. Participants were asked to produce responses differing in sequence length (1-key vs. 3-key responses) with either their left or right hand in a choice reaction time (RT) task. The choice response context was manipulated by a blocked or mixed execution of 1-key and 3-key responses. A sequence length effect on RT was observed in the blocked but not in the mixed condition. The time course of the lateralized readiness potential indicates a motoric locus of the sequence length effect, suggesting that the response hand is activated before the entire motor program is established.

The mismatch negativity as an index of temporal processing in audition.

T Kujala — 2008-04-18T09:18:44-00:00

Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology, Vol. 112, No. 9. (September 2001), pp. 1712-1719.

OBJECTIVES: The relation of the mismatch negativity (MMN) elicitation with behavioral stimulus discrimination as well as the replicability of the MMN was evaluated for intervals between paired tones. METHODS: The MMN, obtained in a passive oddball paradigm in two sessions separated by 4-21 days and behavioral responses (button presses to target stimuli) in a separate session were recorded from 10 adult healthy subjects. The standard stimulus (P=0.79) was a tone pair separated by a 120 ms silent inter-stimulus interval (ISI) and the deviant stimuli were tone pairs with an ISI of 100, 60, and 20 ms (P=0.07 for each). RESULTS: The 20 and 60 ms ISI deviant tone pairs elicited a significant MMN during both recording sessions and they were also behaviorally discriminated, whereas neither did the 100 ms ISI deviant pair elicit significant MMN nor was it behaviorally discriminated. Furthermore, there was a significant correlation between the MMN and reaction times to the 20 and 60 ms ISI deviant pairs. The 20 ms ISI deviant stimulus elicited highly replicable MMNs (r=0.75), whereas the less well discriminated 60 ms ISI deviant pair did not (r=0.60). CONCLUSIONS: The MMN reflects discrimination accuracy of temporal sound intervals. Furthermore, when the physical difference between the standard and deviant tone pair in the temporal domain is large, it is elicited with high reliability.

The Myth of the Paperless Office

Abigail Sellen — 2006-06-13T10:01:38-00:00

(2003)

A diary study of work-related reading: design implications for digital reading devices

Annette Adler — 2006-04-19T03:50:35-00:00

(1998), pp. 241-248.

Sharing encountered information: digital libraries get a social life

Catherine Marshall — 2005-04-15T19:11:37-00:00

(2004), pp. 218-227.

Saving and using encountered information: implications for electronic periodicals

Catherine Marshall — 2006-06-13T09:59:54-00:00

(2005), pp. 111-120.

To have and to hold: exploring the personal archive

Joseph Kaye — 2006-08-14T14:42:04-00:00

(2006), pp. 275-284.

The unified software development process

Ivar Jacobson — 2005-06-10T22:53:15-00:00

(1999)

The Rational Unified Process: an introduction

Philippe Kruchten — 2005-06-10T22:51:07-00:00

(1999)

Molecular cloning, characterization and regulation of two different NADH-glutamate synthase cDNAs in bean nodules

Lourdes Blanco — 2008-03-16T16:53:34-00:00

Plant, Cell & Environment, Vol. 31, No. 4. (April 2008), pp. 454-472.

A Tomato Cysteine Protease Required for Cf-2-Dependent Disease Resistance and Suppression of Autonecrosis

Julia Kruger — 2007-06-12T23:52:33-00:00

Science, Vol. 296, No. 5568. (26 April 2002), pp. 744-747.

10.1126/science.1069288

Performance and robustness analysis for structured uncertainty

John Doyle — 2008-03-04T18:26:36-00:00

Decision and Control, 1982 21st IEEE Conference on, Vol. 21 (1982), pp. 629-636.

This paper introduces a nonconservative measure of performance for linear feedback systems in the face of structured uncertainty. This measure is based on a new matrix function, which we call the Structured Singular Value.

Access Rights Administration in Role-Based Security Systems

Matunda Nyanchama — 2005-11-10T19:01:14-00:00

(1994), pp. 37-56.

This paper examines the concept of role-based protection and, in particular, role organization. From basic role relationships, a model for role organization is developed. The role graph model, its operator semantics based on graph theory and algorithms for role administration are proposed. The role graph model, in our view, presents a very generalized form of role organization for access rights administration. It is shown how the model simulates other organizational structures such as...

Lattice-Based Access Control Models

Ravi Sandhu — 2007-08-07T21:59:28-00:00

IEEE Computer, Vol. 26, No. 11. (1993), pp. 9-19.

The objective of this article is to give a tutorial on lattice-based access control models for computer security. The paper begins with a review of Denning's axioms for information #ow policies, which provide a theoretical foundation for these models. The structure of security labels in the military and government sectors, and the resulting lattice is discussed. This is followed bya review of the Bell-LaPadula model, which enforces information #ow policies by means of its simple-security...

Role-based access control models

RS Sandhu — 2006-06-28T17:42:16-00:00

Computer, Vol. 29, No. 2. (1996), pp. 38-47.

Security administration of large systems is complex, but it can be simplified by a role-based access control approach. This article explains why RBAC is receiving renewed attention as a method of security administration and review, describes a framework of four reference models developed to better understand RBAC and categorizes different implementations, and discusses the use of RBAC to manage itself

A group of interacting yeast DNA replication genes.

KM Hennessy — 2007-08-28T01:18:04-00:00

Genes Dev., Vol. 5, No. 6. (1 June 1991), pp. 958-969.

Mutations in the cell-division-cycle genes CDC46 and CDC47 were originally isolated as suppressors of mutations in two other cell-division-cycle genes (CDC45 and CDC54). We found several combinations of mutations in these genes that result in allele-specific suppression and synthetic lethality, confirming that this set of genes forms a group of genetically interacting components. Here, we show that the other genes, like CDC46, are all involved in an early step of DNA replication, possibly initiation of DNA synthesis. Mutants defective in each of the four genes exhibit high rates of mitotic chromosome loss and recombination. The mutants appear also to accumulate chromosome damage that can be detected by a novel chromosome electrophoresis assay. Conditional mutants in this group, under fully nonpermissive conditions, show cell-cycle arrest at the beginning of DNA synthesis; under less stringent conditions, some arrest later, in S-phase. The DNA sequence of the CDC46 gene indicates that the protein is a member of a new family of genes apparently required for DNA initiation, with family members now identified in Saccharomyces cerevisiae, Schizosaccharomyces pombe, and mouse cells. 10.1101/gad.5.6.958

HEALTH HAZARDS IN A SMALL AUTOMOTIVE BODY REPAIR SHOP

MA Jayjock — 2008-07-27T01:08:53-00:00

Ann Occup Hyg, Vol. 28, No. 1. (1 January 1984), pp. 19-29.

Significant numbers of occupationally exposed workers are engaged in small operations which are not covered by governmental or other occupational health services. The neighbourhood automotive body repair shop is one such activity. Workers there are regularly exposed, with few effective controls, to solvents, metal pigments and paints, polyester plastic fumes and dusts, noise and vibration. A study at a typical owner-operator shop throughout a 1-yr period revealed high, short-term exposures (relative to available TLV-STEL values) to solvent vapours and occasionally lead and chromium pigments. Conditions were exacerbated by the workers' disinclination to use protective equipment or exhaust ventilation, particularly during cold weather. Although noise and nuisance dust levels were sporadically high, they did not appear to pose a health problem. The possible causation of a Raynaud's syndrome by the use of pneumatic tools and the undefined toxic implications of an aliphatic isocyanate exposure from an enamel curing agent are discussed. 10.1093/annhyg/28.1.19

Estimators for long-range dependence: an empirical study

M Taqqu — 2007-09-11T10:07:17-00:00

(1995)

Various methods for estimating the self-similarity parameter and/or the intensity of long-range dependence in a time series are available. Some are more reliable than others. To discover the ones that work best, we apply the different methods to simulated sequences of fractional Gaussian noise and fractional ARIMA(0; d; 0). We also provide here a theoretical justification for the method of residuals of regression. 1 Introduction Time series with long-range dependence appear in many contexts,...

On the Problem of Hidden Variables in Quantum Mechanics

John Bell — 2006-06-01T20:41:56-00:00

Reviews of Modern Physics, Vol. 38, No. 3. (July 1966), 447.

The demonstrations of von Neumann and others; that quantum mechanics does not permit a hidden variable interpretation; are reconsidered. It is shown that their essential axioms are unreasonable. It is urged that in further examination of this problem an interesting axiom would be that mutually distant systems are independent of one another.

Environment Effects on Surface-Plasmon Spectra in Gold-Island Films Potential for Sensing Applications

Fabrice Meriaudeau — 2008-06-05T12:39:32-00:00

Appl. Opt., Vol. 37, No. 34. (1 December 1998), pp. 8030-8037.

The effects of the local dielectric environment on the surface-plasmon resonances of annealed gold-island films as a potential for sensing applications are studied experimentally and modeled theoretically. Gold-island films were annealed at 600 °C to produce spheroidal shape particles that exhibit well-resolved resonances in polarized, angle-resolved, absorption spectra. These resonances are shifted in different amounts by the depolarization effect of the surrounding medium (liquids with various refraction indices). Cross-section calculations based on nonretarded, single-particle, dielectric interaction for these various configurations are presented and are found to be in good agreement with the experimental observations. The results show an interesting potential for biosensing or environmental monitoring applications.

Synthesis, structural elucidation, electro-chemical behaviour and fungitoxic activity of transition metal(II) mixed-ligand complexes with some Schiff bases

Hitesh Parekh — 2005-12-30T11:46:39-00:00

Toxicological and Environmental Chemistry, Vol. 87, No. 4. (26 December 2005), pp. 449-461.

Synthesis, characterization and biological evaluation of manganese(II), cobalt(II), nickel(II), copper(II), and cadmium(II) complexes with monobasic (NO) and neutral (NN) Schiff bases

Nilesh Patel — 2005-02-15T07:41:31-00:00

Transition Metal Chemistry, Vol. 30, No. 1. (February 2005), pp. 13-17.

A method for identifying the most influential articles in an academic discipline

Garey Durden — 2006-12-18T07:05:17-00:00

Atlantic Economic Journal, Vol. V21, No. 4. (18 December 1993), pp. 1-10.