bluuebunny/crossref_metadata_2025 huggingface dataset:
CLASSES AND INSTANCES
Authors: MOTSCHNIG-PITRIK RENATE , MYLOPOULOS JOHN
Published: November 2004

The power of any information system technology is delimited by the expressiveness of the notation used to represent information. Classification constitutes a fundamental notational structuring mechanism and, not surprisingly, is supported in one form or another by many formal notations intended for data or knowledge modelling. This paper presents an overview of various manifestations of classification mechanisms. Further, characteristic features of classification, such as the form of inheritance allowed from classes to instances, having single or multiple classifications and the structure of the classification hierarchy are identified, discussed, and contrasted. The paper also describes the classification mechanism offered by the knowledge representation language Telos. In Telos, classification is stratified and applicable not only to objects but also to (binary) relationships. The paper argues that these features lead to a more expressive notation, acquired at relatively modest conceptual and computational costs.
A FRAMEWORK FOR SUPPORTING TRIGGERS IN OBJECT-ORIENTED DATABASE SYSTEMS
Authors: KIM WON , LEE YOON-JOON , SEO JUNGYUN
Published: November 2004

An active database system reacts to a set of external events such as a timer interrupt or access to a particular object in the database. A trigger is a general mechanism for active data management, both in the context of a centralized system or a distributed system (including that of autonomous and cooperating agents). It consists of three parts; event specification, integrity constraint specification, and action specification. The event specification in a trigger is a set of events which will cause the condition in the constraint specification to be checked. If the condition is true, the actions in the action specification will be initiated. In this paper, we develop a framework for supporting triggers in object-oriented database systems. The framework consists of a categorization for each of the three components of a trigger. The framework is first cast in the context of the relational model of data, and is then extended to account for object-oriented concepts that constitute an object-oriented data model, including nested objects, methods, and inheritance hierarchy.
SHARING PROCESSES: TEAM COORDINATION IN DESIGN REPOSITORIES
Authors: JARKE MATTHIAS , MALTZAHN CARLOS , ROSE THOMAS
Published: November 2004

Information systems support for design environments emphasizes object management and tends to neglect the growing demand for team support. Process management is often tackled by rigid technological protocols which are likely to get in the way of group productivity and quality. Group tools must be introduced in an unobtrusive way which extends current practice yet provides structure and documentation of development experiences. The concept of sharing processes allows agents to coordinate the sharing of ideas, tasks, and results by interacting protocol automata which can be dynamically adapted to situational requirements. Inconsistency is managed with equal emphasis as consistency. The sharing process approach has been implemented in a system called ConceptTalk which has been experimentally integrated with design environments for information and hypertext systems.
INTEGRATING DISTRIBUTED EXPERTISE
Authors: SIMOUDIS EVANGELOS , ADLER MARK
Published: November 2004

Over the past ten years a myriad of knowledge-based expert systems have been developed and deployed. These systems have a narrow scope and usually operate in stand-alone mode. They also follow different implementation philosophies and use a variety of reasoning methods. To address problems of wider scope, researchers have developed systems that utilize either centralized or distributed computational models. Each of these systems is homogeneous, and due to the way developed, prohibitively expensive for real-world settings. In this paper we present OMNI, a framework for integrating existing knowledge-based systems in a way that they can cooperate during problem-solving while they remain distributed over a computing environment.
TOWARDS A MODEL FOR MULTIDATABASE TRANSACTIONS
Authors: RUSINKIEWICZ MAREK , KRYCHNIAK PIOTR , CICHOCKI ANDRZEJ
Published: November 2004

In many application areas the information that may be of interest to a user is stored under the control of multiple, autonomous database systems. To support global transactions in a multidatabase environment, we must coordinate the activities of multiple Database Management Systems that were designed for independent, stand-alone operation. The autonomy and heterogeneity of these systems present a major impediment to the direct adaptation of transaction management mechanisms developed for distributed databases. In this paper we introduce a transaction model designed for a multidatabase environment. A multidatabase transaction is defined by providing a set of (local) sub-transactions, together with their precedence and dataflow requirements. Additionally, the transaction designer may specify failure atomicity and execution atomicity requirements of the multidatabase transaction. These high-level specifications are then used by the scheduler of a multidatabase transaction to assure that its execution satisfies the constraints imposed by the semantics of the application. Uncontrolled interleaving of multidatabase transactions may lead to the violation of interdatabase integrity constraints. We discuss the issues involved in a concurrent execution of multidatabase transactions and propose a new concurrency control correctness criterion that is less restrictive than global serializability. We also show how the multidatabase SQL can be extended to allow the user to specify multidatabase transactions in a nonprocedural way.
THE SMALL ENTERPRISE ENVIRONMENTAL MATRIX: A TOOL FOR STRATEGICALLY POSITIONING SMALL BUSINESS ASSISTANCE PROGRAMS
Authors: HOWARD DENNIS , HINE DAMIAN
Published: November 2004

This paper commences by discussing Small Business Assistance Programs (SBAPs) including why they are necessary, how they work and when they should be employed. This sets the fundamental parameters upon which to base the design of SBAPs. But there is little in the literature, apart from rudimentary planning models to help with strategic positioning of SBAPs in a government policy context. The Small Enterprise Environment Matrix (SEEM) is proposed as a conceptually simple yet potentially useful tool to help policy-makers. It is based on the popular portfolio/matrix approach to strategic decision-making.
RESEARCH STRATEGIES FOR INCREASING NEW KNOWLEDGE DISCOVERY
Authors: GEURSEN GUS M
Published: November 2004

The purpose of this paper is to examine a traditional academic research model frequently used in scholarly papers and the implications of this model in restricting growth and quality of new knowledge generation. The paper contends a traditional academic research process (TARP) is evident in business and the other social science research. It identifies concerns about the process and how it restricts new theory development. The paper provides an alternative model, the higher academic research model (HARP) which is characterised by closer interaction between research processes and phenomena under investigation. The paper concludes by demonstrating the increased output achievement of the new model.
SQUEEZING THE ASIAN ENTREPRENEURIAL ENGINE: THE IMPACT OF THE CREDIT SQUEEZE ON SUSTAINABLE ENTREPRENEURIAL JOB CREATION IN ASIA
Authors: HALL CHRIS
Published: November 2004

Firms in Japan, China, Indonesia, Korea, and most of the rest of Asia, are now facing a prolonged period of very tight credit. Because many banks in the region need to increase their capital adequacy ratios and reduce their risk exposure, most are now unwilling to lend to small, fast growing firms. However, mounting evidence from OECD suggests that the bulk of net job creation comes from a relatively small proportion of fast growing SMEs. The ability to create new jobs will be especially important in Asia in the coming years, and it is unlikely that government infrastructure projects and large firms will be able to provide the job growth required.
DEVELOPMENT AND MARKETING OF INTERACTIVE ENTERTAINMENT SOFTWARE
Authors: DIXON GORDON , KARBOULONIS PETER
Published: November 2004

This paper examines the entertainment software industry within a market perspective. It addresses marketing issues such as acquisitions, mergers, franchising, direct investment, and collaborative arrangements, in an industry where there is significant change in business activity. New entrants in this highly competitive and high value market are identified as being more likely to be developers rather than publishers. Consumer spending in Europe alone for games and interactive entertainment is expected to rise to US $6.1 billion within three years, and by 2002 on-line game players are expected to number five million. Trends point to the income from computer games software and video games surpassing major box office receipts of the motion picture industry. Markets are also emerging to satisfy new classes of consumers both in Europe and in Asia.
WHAT SHOULD BE THE ROLE OF GOVERNMENT IN INNOVATION PROJECTS? SOME PROPOSALS FROM THE SPIN PROJECT IN BRAZIL
Authors: DA SILVA FABIO Q. B.
Published: November 2004

This article describes an strategy for local sustainable development based on the establishment of a State System of Innovation (called SPIN), at the State of Pernambuco in the Northeast Region of Brazil. The conceptual underpinnings of this system consider that, to be competitive in the global economy, any local community must be capable of creating world class businesses and enterprises. Therefore, SPIN has the goal structuring the conditions for the flourishing of a world class knowledge base economy. The conceptual model, the elements of a State development policy and the operating agents of this Innovation System are described.
VENTURE CAPITALISTS' GOVERNANCE OF THEIR PORTFOLIO COMPANIES
Authors: FREDRIKSEN ØYSTEIN , KLOFSTEN MAGNUS
Published: November 2004

Several sources have emphasized the importance of the entrepreneurial economy, and the role venture capitalists (VCs) plays as financiers. VCs are often actively and personally involved in their portfolio companies, but the cost of governance is high and they therefore have to select when to be active participants. Four different risks are identified in this paper: agency risk, business and market risk, coalition risk, and conformity risk. Weak support is found for the categories of agency and business and market risk. The data speak in favor of VCs getting more involved when the portfolio companies experience some kind of trouble. Their activity level increases when the portfolio companies have an inexperienced CEO, when the companies are in an early stage of their development, are young, have a weak board of directors, and/or a weak performance.
AN IMPACT ON PERFORMANCE OF FOREIGN MARKET ENTRY CHOICES BY SMALL AND MEDIUM-SIZED ENTERPRISES
Authors: CHOO STEPHEN , MAZZAROL TIM
Published: November 2004

A firm's performance in the host country to a great extent depends on its mode of market entry. Most research in the area of foreign market entry mode choice has concentrated on large firms or multi-national enterprises. This paper examines the effects of different foreign market entry modes on the performance of small and medium-size enterprises (SMEs) in Australia and Singapore. The data from a sample of 104 SMEs suggests that four market entry modes - licensing, manufacturing/wholly-owned subsidiary, franchising, and acquisition significantly impact performance. It was found that Singaporean firms were more likely to use these market entry modes than their Australia counterparts. This study also reveals that good performers tend to be relatively internationalised, in better control over their export channels, less dependent on industry information sources, and more concerned over loss of proprietary rights to knowledge. Implications of the findings for research and practice are also discussed.
ORGANIZATIONAL INFLUENCES UPON THE DEVELOPMENT OF PROFESSIONAL EXPERTISE IN SMES IN THE NETHERLANDS
Authors: VAN DER HEIJDEN BEATRICE I. J. M.
Published: November 2004

The present study describes the relationship between four organizational predictor variables and the degree of professional expertise of middle and higher level employees in three different career stages, working in small and medium-sized enterprises. Professional expertise is operationalized by means of five dimensions, i.e. knowledge, meta-cognitive knowledge, skills, social recognition and growth and flexibility. The predictors in question are: the amount of social support from one's immediate supervisor, the amount of social support from one's near colleagues, organizational facilities and attention from the direct supervisor to the employee's further career development. Hypotheses have been tested with original survey data from 233 employees and 217 direct supervisors.
ENTREPRENEURIAL DEVELOPMENT: UNDERSTANDING AND MANAGING CHANGE IN THE ENTREPRENEURIAL PROCESS
Authors: CHEAH HOCK BENG
Published: November 2004

In the Management field, the term 'organisational development' refers to the processes of understanding and managing organisational change. Similarly, in the field of Entrepreneurship, we may apply the term 'entrepreneurial development' to the processes of understanding and managing change in the entrepreneurial process.
STRATEGIC MARKETING IN TECHNOLOGY-BASED NEW VENTURES: EXPLORATION OF A PUZZLE
Authors: RAY DENNIS M.
Published: November 2004

The purpose of this article is to explore the foundations of the strategic marketing concept in technology-based new ventures and illustrate the various meanings of strategic marketing through an analysis of a series of vignettes and a New Zealand mini-case study. The intent is to clarify the concept of strategic marketing and create a model of the strategic marketing process in a new venture.
FROM PLANNED ECONOMY CULTURE TO ENTREPRENEURIAL CULTURE: THE EXAMPLE OF BULGARIAN AND ROMANIAN ORGANISATIONS
Authors: KELEMEN MIHAELA , HRISTOV LATCHEZAR
Published: November 2004

The dismantling, in 1989, of the socialist mode of production and distribution in Bulgaria and Romania has marked the beginning of a turbulent and unprecedented period which has had dramatic implications on organisational survival. Some organisations have adapted well to the demands of the so called transition period, others have collapsed in no time. The paper explores the process of change from planned economy culture to entrepreneurial culture in four Bulgarian organisations and four Romanian organisations which have managed to establish themselves as quality suppliers for the Western market. The research methodology consists in in-depth interviews conducted with senior managers as well as an analysis of organisational documents. The theoretical model proposed by the paper is grounded in data, being developed according to Eisenhardt's (1989) methodology. Thus, the change from planned economy culture to entrepreneurial culture is mapped along five dimensions namely, strategic orientation, organisational structure, commitment to quality, technological innovation and control of resources. This theoretical framework has explanatory power only within the organisational settings explored, making no claims to absolute truth or generalisability. However, the model may serve as a working formula for other organisations facing similar pressures.
AN INVESTIGATION OF THE RELATIONSHIP BETWEEN A FIRM'S PERCEIVED EXPORT BARRIERS AND STAGES OF EXPORT DEVELOPMENT: AN ANALYSIS OF CANTERBURY MANUFACTURING FIRMS
Authors: DEAN DAVID , GAN CHRISTOPHER , MYERS CHRISTOPHER
Published: November 2004

Export continues to have positive impact on a country's economy and the economic success of the firms involved. As a result, export expansion and development programs are commonly undertaken to help firms initiate or expand export activities. The objectives of such programs are to provide firms with the opportunities, incentives, information, and resources required to exploit exporting opportunities.

Research on export behaviour suggests that differentiating firms by their stage of export development is one of the effective ways of grouping firms for export development intentions. However, little research has focused on the correlation between export barriers and exporting stages. This research analyses the relationship between a firm's comprehension of export and its stage of export development based on a group of Canterbury manufacturing firms. The results identify two types of export barriers; those that were stable across stages of export development and those which changed in their level of importance across the stages.
A PARSIMONIOUS CONTINUOUS TIME MODEL OF EQUITY INDEX RETURNS: INFERRED FROM HIGH FREQUENCY DATA
Authors: BEDENDO MASCIA , HODGES STEWART D.
Published: November 2004

In this paper we propose a continuous time model capable of describing the dynamics of futures equity index returns at different time frequencies. Unlike several related works in the literature, we avoid specifying a model a priori and we attempt, instead, to infer it from the analysis of a data set of 5-minute returns on the S&P500 futures contract. We start with a very general specification. First we model the seasonal pattern in intraday volatility. Once we correct for this component, we aggregate intraday data into a daily volatility measure to reduce the amount of noise and its distorting impact on the results. We then employ this measure to infer the structure of the stochastic volatility model and of the leverage component, as well as to obtain insights on the shape of the distribution of conditional returns. Our model is then refined at a high frequency level by means of a simple nonlinear filtering technique, which provides an intraday update of volatility and return density estimates on the basis of observed 5-minute returns. The results from a Monte Carlo experiment indicate that a sample of returns simulated according to our model successfully replicates the main features observed in market returns.
ON THE VALIDITY OF THE RANDOM WALK HYPOTHESIS APPLIED TO THE DHAKA STOCK EXCHANGE
Authors: HASAN MOHAMMAD S.
Published: November 2004

This paper employs a battery of statistical tests to examine the random walk variant of the weak-form efficient market hypothesis (EMH) using the daily data of the Dhaka Stock Exchange, the major equity market of Bangladesh, over a period of January 1990 to December 2000. The test results, however, are at variance across testing procedures and sub-periods. Results based on the random walk model and unit root tests show that the null hypothesis of randomness cannot be rejected and stock prices have a significant random walk or permanent component. Our analysis of autocorrelation functions indicates mean-reversion behavior of stock returns in most cases albeit with stock returns exhibiting some memory and predictable components during the bubble and post-speculation periods. The evaluation of the EGARCH-M model suggests significant asymmetric and leverage effects during the sub-period of speculative bubbles of 1996–1997. The BDS test indicates evidence of nonlinear long-term dependence during the pre-speculation period, while during the speculation and post-speculation periods the null hypothesis of nonlinear independence was not rejected. Overall, based on this evidence we do not categorically claim that the Dhaka Stock Exchange is weak-form efficient. However, these findings underscore the predictive significance and relevance of the random walk hypothesis as a generalized theory in explaining movements of share prices.
AN EXTREME VALUE THEORY APPROACH TO THE ALLOCATION OF MULTIPLE ASSETS
Authors: BRADLEY BRENDAN O. , TAQQU MURAD S.
Published: November 2004

We investigate the portfolio construction problem for risk-averse investors seeking to minimize quantile based measures of risk. Using dependence measures from extreme value theory, we find that most international equity markets are asymptotically independent. We also find that the few cases of asymptotic dependence occur mostly in markets which are in close geographic proximity. We then examine how extremal dependence affects the asset allocation problem. Following the structure variable approach, we focus on the portfolio and model its tail in a manner consistent with extreme value theory. We then develop a methodology for asset allocation where the goal is to guard against catastrophic losses. The methodology is tested through simulations and applied to portfolios made up of two or more international equity markets. We analyze in detail three typical types of markets, one where the assets are asymptotically independent and the ratio of marginal risks is not constant, the second where the assets are asymptotically independent but the ratio of marginal risks are approximately constant and the third where the assets are asymptotically dependent and the ratio of marginal risks is not constant. The results are compared with the optimal portfolio under the assumption of normally distributed returns. Surprisingly, we find that the assumption of normality incurs only a modest amount of extra risk for all but the largest losses. We make the software written in support of this work freely available and describe its use in the appendix.
Identification and localization of sodium-phosphate cotransporters in hepatocytes and cholangiocytes of rat liver
Authors: Frei Pascal , Gao Bo , Hagenbuch Bruno , Mate Alfonso , Biber Jürg , Murer Heini , Meier Peter J. , Stieger Bruno
Published: November 2004

Hepatocytes and cholangiocytes release ATP into bile, where it is rapidly degraded into adenosine and Pi. In rat, biliary Piconcentration (0.01 mM) is ∼100-fold and 200-fold lower than in hepatocytes and plasma, respectively, indicating active reabsorption of biliary Pi. We aimed to functionally characterize canalicular Pireabsorption in rat liver and to identify the involved Pitransport system(s). Pitransport was determined in isolated rat canalicular liver plasma membrane (LPM) vesicles using a rapid membrane filtration technique. Identification of putative Pitransporters was performed with RT-PCR from liver mRNA. Phosphate transporter protein expression was confirmed by Western blotting in basolateral and canalicular LPM and by immunofluorescence in intact liver. Transport studies in canalicular LPM vesicles demonstrated sodium-dependent Piuptake. Initial Piuptake rates were saturable with increasing Piconcentrations, exhibiting an apparent Kmvalue of ∼11 μM. Pitransport was stimulated by an acidic extravesicular pH and by an intravesicular negative membrane potential. These data are compatible with transport characteristics of sodium-phosphate cotransporters NaPi-IIb, PiT-1, and PiT-2, of which the mRNAs were detected in rat liver. On the protein level, NaPi-IIb was detected at the canalicular membrane of hepatocytes and at the brush-border membrane of cholangiocytes. In contrast, PiT-1 and PiT-2 were detected at the basolateral membrane of hepatocytes. We conclude that NaPi-IIb is most probably involved in the reabsorption of Pifrom primary hepatic bile and thus might play an important role in the regulation of biliary Piconcentration.
Sarcolemmal KATP channel triggers delayed ischemic preconditioning in rats
Authors: Patel Hemal H. , Gross Eric R. , Peart Jason N. , Hsu Anna K. , Gross Garrett J.
Published: November 2004

Previous work from our laboratory has shown that the sarcolemmal KATP channel (sKATP) is required as a trigger for delayed cardioprotection upon exogenous opioid administration. We also established that the mitochondrial KATP (mKATP) channel is not required for triggering delayed δ-opioid-induced infarct size reduction. Because mechanistic differences have been found among δ-opioids and that due to ischemic preconditioning (IPC), we determined whether the triggering mechanism of delayed IPC-induced infarct size reduction involves either the sKATP or mKATP. Male Sprague-Dawley rats received either sham surgery or IPC (3- to 5-min cycles of ischemia and reperfusion) 24 h before being subjected to 30 min of ischemia and 2 h of reperfusion. Infarct size was determined and expressed as a percentage of the area at risk, with significance compared with sham reported at P ≤ 0.001. A subset of both sham and IPC-treated rats received either the selective sKATP channel antagonist, HMR-1098 (6 mg/kg), or the selective mKATP channel antagonist, 5-hydroxydeconoic acid (5-HD; 10 mg/kg), given 5 min before IPC. Rats subjected to IPC demonstrated a significant reduction in infarct size compared with sham (29.2 ± 4.7 vs. 59.3 ± 2.5%, respectively; P ≤ 0.001). Prior administration of HMR-1098, but not 5-HD, abolished IPC-induced infarct size reduction (48.8 ± 2.9 and 28.8 ± 4.0%, respectively; P ≤ 0.001). Furthermore, administration of HMR 24 h after IPC, before index ischemia, did not abrogate IPC-induced infarct size reduction (33.0 ± 5.0 vs. 29.2 ± 4.7%, respectively; P ≤ 0.001). These data suggest that the sKATP channel is required as a trigger but not a mediator for delayed IPC-induced infarct size reduction in rat hearts.
Sodium channel enhancer restores baroreflex sensitivity in conscious dogs with heart failure
Authors: Shen Weiqun , Gill Robert M. , Zhang Jian-Ping , Jones Bonita D. , Corbly Angela K. , Steinberg Mitchell I.
Published: November 2004

We compared the cardiac inotropic, lusitropic, and chronotropic responses to the Na+ channel enhancer LY-368052 in conscious dogs before and after development of congestive heart failure (CHF). We also examined the effect of LY-368052 on baroreflex sensitivity and the efferent neural mechanisms of the bradycardic response in heart failure. Dogs were chronically instrumented, and heart failure was induced by right ventricular pacing at 240 beats/min for 3–4 wk. LY-368052 dose-dependently increased left ventricular contractile performance before and after the development of CHF to a similar extent. The inotropic effect of LY-368052 in heart failure was not altered by either ganglionic or β-adrenergic receptor blockade. LY-368052 improved cardiac relaxation and induced bradycardia in dogs with heart failure but not in normal dogs. The negative chronotropic effect of LY-368052 was eliminated by ganglionic blockade but not β-adrenergic blockade, suggesting that the bradycardia was mediated by the autonomic nervous system via enhanced parasympathetic tone. Baroreflex sensitivity was assessed as the pulse interval-mean arterial pressure slope in response to temporary pharmacological (nitroglycerin or phenylephrine) and mechanical (brief occlusion of inferior vena cava) alterations of arterial pressure in conscious dogs before and after development of heart failure. Baroreflex sensitivity was significantly depressed in heart failure and restored completely by acute treatment with LY-368052. Thus the Na+ channel enhancer LY-368052 maintains its β-receptor-independent inotropic effect in chronic CHF and specifically improves ventricular relaxation and depressed baroreflex function.
Plasma ATP during exercise: possible role in regulation of coronary blood flow
Authors: Farias Martin , Gorman Mark W. , Savage Margaret V. , Feigl Eric O.
Published: November 2004

It was previously shown that red blood cells release ATP when blood oxygen tension decreases. ATP acts on microvascular endothelial cells to produce a retrograde conducted vasodilation (presumably via gap junctions) to the upstream arteriole. These observations form the basis for an ATP hypothesis of local metabolic control of coronary blood flow due to vasodilation in microvascular units where myocardial oxygen extraction is high. Dogs ( n = 10) were instrumented with catheters in the aorta and coronary sinus, and a flow transducer was placed around the circumflex coronary artery. Arterial and coronary venous plasma ATP concentrations were measured at rest and during three levels of treadmill exercise by using a luciferin-luciferase assay. During exercise, myocardial oxygen consumption increased ∼3.2-fold, coronary blood flow increased ∼2.7-fold, and coronary venous oxygen tension decreased from 19 to 12.9 mmHg. Coronary venous plasma ATP concentration increased significantly from 31.1 to 51.2 nM ( P < 0.01) during exercise. Coronary blood flow increased linearly with coronary venous ATP concentration ( P < 0.01). Coronary venous-arterial plasma ATP concentration difference increased significantly during exercise ( P < 0.05). The data support the hypothesis that ATP is one of the factors controlling coronary blood flow during exercise.
Shunting Inhibition in Accessory Optic System Neurons
Authors: Ariel Michael , Kogo Naoki
Published: November 2004

The interaction of excitatory and inhibitory inputs to the accessory optic system was studied with whole cell recordings in the turtle basal optic nucleus. Previous studies have shown that visual patterns, drifting in the same preferred direction, evoke excitatory and inhibitory postsynaptic events simultaneously. Analysis of the reversal potentials for these events and their pharmacological profile suggest that they are mediated by AMPA and GABAA receptors, respectively. Here, neurons were recorded to study nonlinear interaction between excitatory and inhibitory responses evoked by electrical microstimulation of the retina and pretectum, respectively. The responses to coincident activation of excitatory and inhibitory inputs exhibited membrane shunting in that the excitatory response amplitude, adjusted for changes in driving force, was attenuated during the onset of the inhibitory response. This nonlinear interaction was seen in many but not all stimulus pairings. In some cases, attenuation was followed by an augmentation of the excitatory response. For comparison, the size of the excitatory response was evaluated during a hyperpolarizing current pulse that directly modulated voltage-sensitive channels of a slow rectifying Ih current. Injection of hyperpolarizing current did not cause the attenuation of the excitatory synaptic responses. We conclude that there is a nonlinear interaction between these excitatory and inhibitory synaptic currents that is not due to hyperpolarization itself, but probably is a result of their own synaptic conductance changes, i.e., shunting. Since these events are evoked by identical visual stimuli, this interaction may play a role in visual processing.
Hepatitis B Virus Genotypes and Hepatocellular Carcinoma in Taiwan
Authors: Kao Jia-Horng
Published: November 2004

With phylogenetic analysis of hepatitis B virus (HBV) isolates, eight different genotypes (A to H) have been recognized worldwide. The impact of HBV genotypes on the clinical aspects of HBV infection in Taiwan, including the clinical outcome of chronic infection and therapeutic response to antiviral treatments, has been clarified. Our data showed that genotypes B and C are the predominant HBV strains in Taiwan, and genotype C is associated with more severe liver disease including cirrhosis and hepatocellular carcinoma (HCC), whereas genotype B is associated with the development of HCC in young noncirrhotic patients. Serologically, genotype C tends to have a higher frequency of hepatitis B e antigen (HBeAg) positivity and a higher serum HBV DNA level than genotype B. In addition, genotype C patients, compared to genotype B patients, have a delayed HBeAg seroconversion in the immune clearance phase of chronic HBV infection. Virologically, genotype C bears a higher frequency of basal core promoter mutation than genotype B. Our recent data further indicated that patients with basal core promoter mutation are significantly more associated with the development of HCC than those without, which applies to both genotypes B and C. In addition, the prevalence of basal core promoter mutation in young HCC patients is comparable to older HCC patients but is significantly higher than that in age-matched inactive carriers, irrespective of genotypes. Although superinfection of HBV on hepatitis B carriers indeed occurs in Taiwan, it is rarely associated with acute exacerbations. As to the response to antiviral treatments, genotype C is associated with a lower response rate to interferon therapy compared to genotype B. In addition, genotype B seems to have a better virological response to lamivudine as compared to genotype C, but both genotypes have a similar risk in the development of lamivudine resistance. These lines of evidence highlight the remarkable differences in the clinical and virological characteristics between Taiwanese patients infected with different genotypes. In conclusion, pathogenic and therapeutic differences do exist among HBV genotypes in Taiwan, and determining the genotype in patients with chronic HBV infection would help gain further information in anthropologic, clinical, virological and prognostic investigations.
Fast Approximate Search in Large Dictionaries
Authors: Mihov Stoyan , Schulz Klaus U.
Published: November 2004

The need to correct garbled strings arises in many areas of natural language processing. If a dictionary is available that covers all possible input tokens, a natural set of candidates for correcting an erroneous input P is the set of all words in the dictionary for which the Levenshtein distance to Pdoes not exceed a given (small) bound k. In this article we describe methods for efficiently selecting such candidate sets. After introducing as a starting point a basic correction method based on the concept of a “universal Levenshtein automaton,” we show how two filtering methods known from the field of approximate text search can be used to improve the basic procedure in a significant way. The first method, which uses standard dictionaries plus dictionaries with reversed words, leads to very short correction times for most classes of input strings. Our evaluation results demonstrate that correction times for fixed-distance bounds depend on the expected number of correction candidates, which decreases for longer input words. Similarly the choice of an optimal filtering method depends on the length of the input words.
Analysis of Cyclic Dynamics for Networks of Linear Threshold Neurons
Authors: Tang H. J. , Tan K. C. , Zhang Weinian
Published: November 2004

The network of neurons with linear threshold (LT) transfer functions is a prominent model to emulate the behavior of cortical neurons. The analysis of dynamic properties for LT networks has attracted growing interest, such as multistability and boundedness. However, not much is known about how the connection strength and external inputs are related to oscillatory behaviors. Periodic oscillation is an important characteristic that relates to nondivergence, which shows that the network is still bounded although unstable modes exist. By concentrating on a general parameterized two-cell network, theoretical results for geometrical properties and existence of periodic orbits are presented. Although it is restricted to two-dimensional systems, the analysis can provide a useful contribution to analyze cyclic dynamics of some specific LT networks of high dimension. As an application, it is extended to an important class of biologically motivated networks of large scale: the winner-take-all model using local excitation and global inhibition.
Efficient Coding of Time-Relative Structure Using Spikes
Authors: Smith Evan , Lewicki Michael S.
Published: November 2004

Nonstationary acoustic features provide essential cues for many auditory tasks, including sound localization, auditory stream analysis, and speech recognition. These features can best be characterized relative to a precise point in time, such as the onset of a sound or the beginning of a harmonic periodicity. Extracting these types of features is a difficult problem. Part of the difficulty is that with standard block-based signal analysis methods, the representation is sensitive to the arbitrary alignment of the blocks with respect to the signal. Convolutional techniques such as shift-invariant transformations can reduce this sensitivity, but these do not yield a code that is efficient, that is, one that forms a nonredundant representation of the underlying structure. Here, we develop a non-block-based method for signal representation that is both time relative and efficient. Signals are represented using a linear superposition of time-shiftable kernel functions, each with an associated magnitude and temporal position. Signal decomposition in this method is a non-linear process that consists of optimizing the kernel function scaling coefficients and temporal positions to form an efficient, shift-invariant representation. We demonstrate the properties of this representation for the purpose of characterizing structure in various types of nonstationary acoustic signals. The computational problem investigated here has direct relevance to the neural coding at the auditory nerve and the more general issue of how to encode complex, time-varying signals with a population of spiking neurons.
Online Ranking by Projecting
Authors: Crammer Koby , Singer Yoram
Published: November 2004

We discuss the problem of ranking instances. In our framework, each instance is associated with a rank or a rating, which is an integer in 1 to k. Our goal is to find a rank-prediction rule that assigns each instance a rank that is as close as possible to the instance's true rank. We discuss a group of closely related online algorithms, analyze their performance in the mistake-bound model, and prove their correctness. We describe two sets of experiments, with synthetic data and with the Each Movie data set for collaborative filtering. In the experiments we performed, our algorithms outperform online algorithms for regression and classification applied to ranking.
Convergence of the IRWLS Procedure to the Support Vector Machine Solution
Authors: Pérez-Cruz Fernando , Bousoño-Calzón Carlos , Artés-Rodríguez Antonio
Published: November 2004

An iterative reweighted least squares (IRWLS) procedure recently proposed is shown to converge to the support vector machine solution. The convergence to a stationary point is ensured by modifying the original IRWLS procedure.
Bilinear Sparse Coding for Invariant Vision
Authors: Grimes David B. , Rao Rajesh P. N.
Published: November 2004

Recent algorithms for sparse coding and independent component analysis (ICA) have demonstrated how localized features can be learned from natural images. However, these approaches do not take image transformations into account. We describe an unsupervised algorithm for learning both localized features and their transformations directly from images using a sparse bilinear generative model. We show that from an arbitrary set of natural images, the algorithm produces oriented basis filters that can simultaneously represent features in an image and their transformations. The learned generative model can be used to translate features to different locations, thereby reducing the need to learn the same feature at multiple locations, a limitation of previous approaches to sparse coding and ICA. Our results suggest that by explicitly modeling the interaction between local image features and their transformations, the sparse bilinear approach can provide a basis for achieving transformation-invariant vision.
Toward Systematic Control of Cybersickness
Authors: Jones Marshall B. , Kennedy Robert S. , Stanney Kay M.
Published: November 2004

Visually induced motion sickness, or “cybersickness”, has been well documented in all kinds of vehicular simulators and in many virtual environments. It probably occurs in all virtual environments. Cybersickness has many known determinants, including (a short list) field-of-view, flicker, transport delays, duration of exposure, gender, and susceptibility to motion sickness. Since many of these determinants can be controlled, a major objective in designing virtual environments is to hold cybersickness below a specified level a specified proportion of the time. More than 20 years ago C. W. Simon presented a research strategy based on fractional factorial experiments that was capable in principle of realizing this objective. With one notable exception, however, this strategy was not adopted by the human factors community. The main reason was that implementing Simon's strategy was a major undertaking, very time-consuming, and very costly. In addition, many investigators were not satisfied that Simon had adequately addressed issues of statistical reliability. The present paper proposes a modified Simonian approach to the same objective (holding cybersickness below specified standards) with some loss in the range of application but a greatly reduced commitment of resources.
Haptic Interfaces for Wheelchair Navigation in the Built Environment
Authors: Harrison Colin S. , Grant Mike , Conway Bernard A.
Published: November 2004

A number of countries have recently introduced legislation aimed at ending discrimination against disabled people; in the United Kingdom the Disability Discrimination Act (1995) provides the disabled community with new employment and access rights. The intention of the act is to help those who rely on wheelchairs for mobility and who frequently find that not all buildings provide conditions suited to easy access. Central to these new rights will be an obligation for employers and organizations to provide premises that do not disadvantage the disabled. This work reports on the development of instrumentation that allows wheelchair navigation within virtual buildings and can assist architects in identifying the needs of wheel-chair users at an early design stage. Central to this project has been the need to provide a platform that can accommodate a range of wheelchair types and will map intended wheelchair motion into a virtual space. This interface must have the capacity to provide feedback to the user reflecting constraints present in the physical world, including changes in floor surface characteristics, gradients, and collisions. Integrating visual and nonvisual sensory feedback correlating to the physical effort of wheelchair propulsion has been found to augment the perception of self-motion within the virtual world and so can create an effective instrument for use in the study of wheelchair accessibility within the built environment. This project represents a collaborative effort between architects and bioengineers engaged in research related to platform design, construction, and interfacing, while testing and evaluation has been accomplished with the assistance of user groups.
Recording Procedures and Legal Culture In the Late Ottoman Shari'a Court Of Jaffa, 1865-1890
Authors: Agmon Iris
Published: November 2004

In the 1870s, a new procedure for recording cases in the shari'a courts was officially introduced by the Ottoman judicial administration. In this essay I explore the implementation of this innovation in the Jaffa court between the years 1865 and 1890. My sources include the Jaffa court records and the Ottoman regulations that specify the instructions about the new recording procedure. I argue that the court of Jaffa was a site of ongoing changes that were part of its legal culture. The judges and court scribes were regularly involved in creating new recording practices through trial and error. Thus, legal reform, from the perspective of the Jaffa court, was not the exclusive domain of the imperial center. The local court played an active role in it.
Literacy, Gender, and Class: Nüshu and Sisterhood Communities In Southern Rural Hunan
Authors: Liu Fei-Wen
Published: November 2004

In this article, I investigate how peasant women in Jiangyong County of southern Hunan defined and practiced a female-specific written script known as nüshu ('female writing'). With an emphasis on sisterhood relationships, I explore how women employed nüshu to construct meaning, experience autonomy, and acknowledge the androcentric impositions made upon them, which in turn highlights the dual nature of nüshu literacy. On the one hand, nüshu empowered women by allowing them to expand female connections beyond the confines of male-derived familial ties and village boundaries; on the other hand, it embodied Jiangyong peasant women's frustration over their failure to sustain such connections after marriage. To contrast nüshu with the gentry women's literary communities in the Lower Yangzi region during late imperial China, this research demonstrates how literacy dynamically interacts with the social forces of gender and class. Whereas female literati's social networks were able to expand and be sustained and even succeeded in penetrating male scholarly circles, nüshu sisterhood communities often failed to survive in face of the challenges set by village exogamy, mainly due to the lack of male support and to Jiangyong's rural context.
Defective Glucose-Stimulated Insulin Release in the Diabetic Goto-Kakizaki (GK) Rat Coincides with Reduced Activity of the Islet Carbon Monoxide Signaling Pathway
Authors: Mosén Henrik , Salehi Albert , Alm Per , Henningsson Ragnar , Jimenez-Feltström Javier , Östenson Claes-Göran , Efendic Suad , Lundquist Ingmar
Published: November 2004

The Goto-Kakizaki (GK) rat displays a markedly reduced insulin response to glucose, a defect that is thought to be coupled to an impaired glucose signaling in the β-cell. We have examined whether carbon monoxide (CO), derived from β-cell heme oxygenase (HO), might be involved in the secretory dysfunction. Immunocytochemical labeling of constitutive HO (HO-2) showed no overt difference in fluorescence pattern in islets from GK vs. Wistar controls. However, isolated islets from GK rats displayed a markedly impaired HO activity measured as CO production (−50%), and immunoblotting revealed an approximately 50% reduction of HO-2 protein expression compared with Wistar controls. Furthermore, there was a prominent expression of inducible HO (HO-1) in GK islets. Incubation of isolated islets showed that the glucose-stimulated CO production and the glucose-stimulated insulin response were considerably reduced in GK islets compared with Wistar islets. Addition of the HO activator hemin or gaseous CO to the incubation media brought about a similar amplification of glucose-stimulated insulin release in GK and Wistar islets, suggesting that distal steps in the HO-CO signaling pathway were not appreciably affected. We conclude that the defective insulin response to glucose in the GK rat can be explained, at least in part, by a marked impairment of the glucose-HO-CO signaling pathway as manifested by a prominent decrease in glucose stimulation of islet CO production and a reduced expression of HO-2. A possible role of HO-1 expression as a compensatory mechanism in the GK islets is presently unclear.
Lipopolysaccharide Directly Stimulates Cortisol Secretion by Human Adrenal Cells by a Cyclooxygenase-Dependent Mechanism
Authors: Vakharia K. , Hinson J. P.
Published: November 2004

Activation of the hypothalamo-pituitary-adrenal axis by bacterial lipopolysaccharide (LPS; endotoxin) is well documented, although there has been uncertainty about whether LPS exerts a direct effect at the level of the adrenal. The present study found that LPS caused a dose-dependent stimulation of basal cortisol secretion by the human adrenocortical cell line, NCI-H295R, without affecting aldosterone. The expression of both Toll-like receptor 2 (TLR2) and TLR4 was demonstrated in these cells, and the specific ligands for TLR4 (purified LPS and lipid A) and TLR2 (Pam3Cys) were found to stimulate cortisol release, suggesting that these receptors may mediate the effects of LPS in adrenal cells, as has been shown in other cell types. LPS was also found to stimulate prostaglandin E2 release by these cells. The effects of LPS on cortisol were attenuated in the presence of both indomethacin and a specific COX-2 inhibitor, but not a COX-1 inhibitor, suggesting an obligatory role for COX-2 activation and prostaglandin synthesis in the adrenal response to LPS.