bluuebunny/crossref_metadata_2025 huggingface dataset:
CRITICAL BEHAVIOR OF THE SPECIFIC HEAT IN THE VICINITY OF THE TRANSITION TEMPERATURE FOR S-TRIAZINE
Authors: KURT M. , YURTSEVEN H.
Published: April 2009

The critical behavior of the specific heat is studied in s-triazine ( C3N3H3). Using the experimental data for the CP, the temperature dependence of the specific heat is analyzed according to a power-law formula and the values of the critical exponent for CPare extracted in the vicinity of the transition temperature (TC=198.07 K ).

It is indicated that s-triazine undergoes a weakly first order (quasi-continuous) or second order phase transition.
LEARNING NEGOTIATION POLICIES USING ENSEMBLE-BASED DRIFT DETECTION TECHNIQUES
Authors: ENEMBRECK FABRÍCIO , TACLA CESAR AUGUSTO , BARTHÈS JEAN-PAUL
Published: April 2009

In this work we compare drift detection techniques and we show how they can improve the performance of trade agents in multi-issue bilateral dynamic negotiations. In a dynamic negotiation the utility values and functions of trade agents can change on the fly. Intelligent trade agents must identify and take such drift in the competitors into account changing also the offer policies to improve the global utility throughout the negotiation. However, traditional learning mechanisms disregard possible changes in a competitor's offer/counter-offer policy. In that case, the agent performance may decrease drastically. In our approach, a trade agent has a staff of weighted learner agents used to predict interesting offers. The staff uses the Dynamic Weighted Majority (DWM) algorithm to adapt itself creating, deleting and adapting staff members. The results obtained with the IB3 (Instance-based) learners and IB3-DWM learners show that ensemble methods like DWM are suitable for correctly identifying changes in agent negotiations.
PERSONALIZING THE SOURCE SELECTION AND THE RESULT MERGING PROCESS
Authors: KECHID SAMIR , DRIAS HABIBA
Published: April 2009

The World Wide Web knows an incessant and very fast development. Currently, finding useful information on the Web is a time consuming process. In this paper, we present PIRS a personalized Information Retrieval System in a distributed environment. Most prior research in distributed information access focused on selecting and merging information that has the most relevant content according to the query but ignored the user's specific needs. The underlying idea is that different users have different backgrounds, goals and interests when seeking information and thus, the same query may cover different specific information needs according to who emitted it. However, with the ever expanding Web, users are faced with a huge number of information resources. Consequently, such query-based information access strategies lead to inaccurate query results. PIRS extends the state of the art in a Web-based information retrieval system in distributed environment. First, it develops models for representing both user and information source using feature based profiles. Second, PIRS expands a user query according to his profile. Third, it develops algorithms for source selection and results merging that personalize the computation of the relevance score of a document in response to the user's query. PIRS has been experimented with several known information source. The experimental results obtained show the effectiveness of our approach.
UNIFORMLY DISTRIBUTED PARETO FRONTS THROUGH THE MAXIMIN SELECTION ALGORITHM
Authors: PEÑA SERGIO I. VALDEZ , RIONDA SALVADOR BOTELLO , AGUIRRE ARTURO HERNÁNDEZ
Published: April 2009

This paper introduces the MaxiMin selection algorithm, a deterministic procedure to achieve maximal spread and almost perfectly distributed Pareto fronts. MaxiMin is successful because the measure of uniformity is performed on the set being constructed, not on the source set as most multi-objective algorithms do. For comparison purposes we present results delivered by several MOEAs with and without the MaxiMin selection. Performance metrics and graphical results show that MaxiMin improves the distribution and spread of Pareto fronts, with no negative effects on the convergence performance of the multi-objective algorithm.
A PARTIAL ORDERING OF KNOTS AND LINKS THROUGH DIAGRAMMATIC UNKNOTTING
Authors: DIAO YUANAN , ERNST CLAUS , STASIAK ANDRZEJ
Published: April 2009

In this paper we define a partial ordering of knots and links using a special property derived from their minimal diagrams. A link [Formula: see text] is called a predecessor of a link [Formula: see text] if [Formula: see text] and a diagram of [Formula: see text] can be obtained from a minimal diagram D of [Formula: see text] by a single crossing change. In such a case, we say that [Formula: see text]. We investigate the sets of links that can be obtained by single crossing changes over all minimal diagrams of a given link. We show that these sets are specific for different links and permit partial ordering of all links. Some interesting results are presented and many questions are raised.
DEHN SURGERY ON SINGULAR KNOTS
Authors: GHUMAN SIMRAT M. , GRANDA LARRY M. , TSAU CHICHEN M.
Published: April 2009

In this paper we extend the idea of Dehn surgery to a singular knot with one singularity, and give conditions under which the surgery manifold of an untangled singular knot is a Haken manifold containing an incompressible torus. We then show that untangled singular knots have Property P.
TANGLE AND BRAUER DIAGRAM ALGEBRAS OF TYPE Dn
Authors: COHEN ARJEH M. , GIJSBERS DIÉ A. H. , WALES DAVID B.
Published: April 2009

A generalization of the Kauffman tangle algebra is given for Coxeter type D n. The tangles involve a pole of order 2. The algebra is shown to be isomorphic to the Birman–Murakami–Wenzl algebra of the same type. This result extends the isomorphism between the two algebras in the classical case, which, in our set-up, occurs when the Coxeter type is A n - 1. The proof involves a diagrammatic version of the Brauer algebra of type D n of which the generalized Temperley–Lieb algebra of type D n is a subalgebra.
GENERALIZED SCALAR–TENSOR THEORY AND THE COSMIC ACCELERATION
Authors: BANERJEE NARAYAN , GANGULY KOYEL
Published: April 2009

In this paper it is shown that a simple functional form of ω(ϕ) in a generalized scalar–tensor theory can drive the present cosmic acceleration without any quintessence field or the cosmological constant Λ. Furthermore, it ensures a smooth transition from a decelerated to an accelerated phase of expansion in the matter-dominated regime.
THE FIRST LAW, COUNTERTERMS AND KERR-AdS5 BLACK HOLES
Authors: AWAD ADEL M.
Published: April 2009

We apply the counterterm subtraction technique to calculate the action and other quantities of the Kerr-AdS black hole in five dimensions using two boundary metrics: the Einstein universe and the rotating Einstein universe with an arbitrary angular velocity. In both cases, the resulting thermodynamic quantities satisfy the first law of thermodynamics. We point out that the reason for the violation of the first law in previous calculations was that the rotating Einstein universe, used as a boundary metric, was rotating with an angular velocity that depended on the black hole rotation parameter. Using a new coordinate system with a boundary metric that has an arbitrary angular velocity, one can show that the resulting physical quantities satisfy the first law.
HOLOGRAPHIC CHAPLYGIN DGP COSMOLOGIES
Authors: SETARE M. R.
Published: April 2009

This paper, presents a model inspired by extra dimensions that is built on the DGP brane-world scenario. The dark energy component on the brane is then taken to be a Chaplygin gas. After that, a holographic model of the Chaplygin gas in the framework of DGP cosmology is considered. It is shown that the holographic Chaplygin gas can mimic a phantom fluid and cross the phantom divide in a DGP brane-world setup.
GENERALIZED MODEL FOR Λ DARK ENERGY
Authors: MUKHOPADHYAY UTPAL , RAY P. C. , RAY SAIBAL , DUTTA CHOUDHURY S. B.
Published: April 2009

Einstein field equations under spherically symmetric space–times are considered here in connection with dark energy investigation. A set of solutions is obtained for a kinematic Λ model, viz. [Formula: see text], without assuming any a priori value for the curvature constant and the equation-of-state parameter ω. Some interesting results, such as the nature of cosmic density Ω and deceleration parameter q, have been obtained with the consideration of two-fluid structure instead of the usual unifluid cosmological model.
DISTRIBUTION FUNCTION IN THE CENTER OF THE DARK MATTER HALO
Authors: MA DING , HE PING
Published: April 2009

N-body simulations of dark matter halos show that the density profiles of the halos behave as ρ(r) ∝ r-α(r), where the density logarithmic slope α ≃ 1–1.5 in the center and α ≃ 3–4 in the outer parts of the halos. However, some observations are not in agreement with simulations in the very central region of the halos. The simulations also show that the velocity dispersion anisotropy parameter β ≈ 0 in the inner part of the halo and the so-called pseudo–phase-space density ρ/σ3 behaves as a power law in radius r. With these results in mind, we study the distribution function and the pseudo–phase-space density ρ/σ3 of the center of dark matter halos and find that they are closely related.
ANALYSIS OF A DELAYED PREDATOR-PREY SYSTEM WITH IMPULSIVE STATE FEEDBACK
Authors: LI ZHICONG , LU QISHAO
Published: April 2009

A delayed dynamical system model incorporating modified Leslie–Gower and Holling-type II schemes with state-dependent impulses is investigated for the case of small delay. The boundedness of solutions is analyzed by applying the comparison argument. Existence and stability of the semi-trivial periodic solution and the positive period-1 solution are discussed by using the variational principle, constructing Poincaré map and applying Floquet multiplier theory. Flip bifurcation is also investigated and some numerical simulation is presented in detail.
A RANDOM CLUSTER PROCESS APPROACH TO COLLECTIVE MARKET DYNAMICS WITH LOCAL INTERACTIONS
Authors: CAI HAIYAN , CHEN KANG
Published: April 2009

In this paper, we adopt an agent-based approach to model collective market dynamics when interactions between the agents in a market are significant. Our model has two special features. First, social groups are formed in a random cluster process which, we believe, mimics the actual formation of social circles. Second, the process is shown to have an equilibrium distribution which gives the highest probability to the market configurations with the maximum total likelihood. With this model we are able to catch some key characteristics of collective dynamics emerged from agent interactions. These characteristics include, for example, a heavy-tailed distribution for the market returns.
NONLINEAR ELASTO-DYNAMIC ANALYSIS OF I-BEAMS CURVED IN-PLAN
Authors: ERKMEN R. EMRE , BRADFORD MARK A.
Published: April 2009

The elastic response of curved beams subjected to moving vertical loads and dynamic loads is investigated. Incremental dynamic equilibrium equations are derived by using the principle of virtual work. Newmark's step-by-step procedure is adopted to discretise the dynamic equilibrium equations and obtain the time history response. Geometric nonlinearities due to large deflections and rotations are taken into account. A total Lagrangian finite element formulation is developed. The numerical models are compared with the existing analytical solutions and employed to show the effects of geometric nonlinearities as well as the initial curvature on the dynamic behaviour of curved I-beams. It is shown that the geometric nonlinearities are significant even for service loads. The nonlinear behaviour of a curved beam is substantially different from the nonlinear behaviour of a straight beam when the initial curvature is not small.
EXPERIMENTAL AND ANALYTICAL INVESTIGATIONS OF SCAFFOLDS WITH ANCHOR ROD AND PLANK
Authors: PENG JUI-LIN , CHEN KUAN-HUNG , CHAN SIU-LAI , CHEN WEI-TONG
Published: April 2009

This paper investigates the influence of anchor rods, planks and inner knee braces on the critical load of scaffolding systems under concentric and eccentric loads in construction. The steel rebar of grade 3 is used in place of the patent anchor rod in this study. The results show that the critical load of the scaffolding system increases by 1.5 times when anchor rods of a length of 30 cm are used on two sides of each story of the scaffolding system. The critical load increases by 4 times when the scaffolding system has both the anchor rods and plank. The critical load of the scaffolding system with the anchor rods placed on each story is twice as large as that with anchor rods added every two stories; the failure mode of the system also switches from the in-plane to out-of-plane mode. The 30-cm-long anchor rod, used in place of a steel bar of grade 3, provides a good lateral restraint to the scaffolding system. Moreover, the setup plank can significantly elevate the critical load of the scaffolding system; the critical load increases approximately 1.5 times under the concentric load, and increases up to 2.2 times under the TL/4 eccentric load, defined as a load applied at a quarter distance from the end. The anchor rod and the plank should always be included in a scaffolding system to improve its stability, especially under the eccentric loads in construction.
SEISMIC RETROFITTING OF CHEVRON-BRACED STEEL FRAMES BASED ON PREVENTING BUCKLING INSTABILITY OF BRACES
Authors: DICLELI MURAT , MEHTA ANSHU
Published: April 2009

In this research, a seismic retrofitting method for chevron-braced frames (CBFs) is proposed. The key idea here is to prevent the buckling of the chevron braces via a conventional construction technique that involves a hysteretic energy-dissipating element installed between the braces and the connected beam. The energy-dissipating element is designed to yield prior to buckling of the braces, thereby preventing the lateral stiffness and strength degradation of the CBF caused by buckling, while effectively dissipating the earthquake input energy. Nonlinear static pushover, time history and damage analyses of the CBF and retrofitted CBF (RCBF) are conducted to assess the performance of the RCBF compared with that of the CBF. The results of the analyses reveal that the proposed retrofitting method can efficiently alleviate the detrimental effects of earthquakes on the CBF. The RCBF has a more stable lateral force–deformation behavior with enhanced energy dissipation capability than the CBF. For small-to-moderate intensity ground motions, the maximum interstory drift of the RCBF is close to that of the CBF. But, for high intensity ground motions, it is considerably smaller than that of the CBF. Compared with the CBF under medium-to-large intensity ground motions, the RCBF experiences significantly less damage due to prevention of buckling of the braces.
QUANTUM SECRET ENCRYPTION AND DECRYPTION IN CAVITY QED
Authors: LI CHE-MING , HSU LI-YI , CHUU DER-SAN
Published: April 2009

We present a proposal of the quantum secret encryption, transmission, and decryption implementation for quantum secret-sharing protocol using cavity QED. In the proposed scheme, the information is stored in two identical two-level atoms, and the two-qubit logic transformation is realized through the interaction between atoms and a nonresonant cavity mode. The proposed scheme requires no ancilla states to assist the intermediate atomic transitions and conditional quantum dynamics for quantum phase flip and quantum state diffusion. The encryption and decryption of quantum states are mostly governed by the Hamiltonian of an atom-cavity system. Moreover, secret transmission using quasi-swap gates for entanglement swapping has also been presented. With fewer supplements of external fields, a speed quantum protocol can be realized without universal gates.
INVESTIGATION OF QUANTUM ROULETTE
Authors: SALIMI S. , SOLTANZADEH M. M.
Published: April 2009

In this paper, by using permutation matrices as a representation of symmetric group SN and Fourier matrix, we investigate quantum roulette with an arbitrary N-state. This strategy, which we introduce, is a general method that allows us to solve quantum game for an arbitrary N-state. We consider the interaction between the system and its environment and study the effect of the depolarizing channel on this strategy. Finally, as an example, we employ this strategy for quantum roulette with N = 3.
ENTANGLEMENT VERSUS ENERGY IN MULTIQUBIT ENTANGLEMENT DYNAMICS PROBLEM
Authors: HAN FENG , XIA YUN-JIE
Published: April 2009

We study the relation between energy and entanglement in a multiqubit entanglement dynamics problem in cavity QED. The model consists of three two-level atoms A, B and C which are initially prepared in a Greenberger–Horne–Zeilinger-like state and locally coupled with independent cavities a, b and c, respectively. We shall show that the dynamical evolution of atomic entanglement is closely related to that of their energy.
QUANTUM SECURE DIRECT COMMUNICATION USING A SIX-QUBIT MAXIMALLY ENTANGLED STATE WITH DENSE CODING
Authors: DONG LI , DONG HAI-KUAN , XIU XIAO-MING , GAO YA-JUN , CHI FENG
Published: April 2009

Using quantum dense coding, a quantum secure direct communication scheme with a six-qubit maximally entangled state is proposed. If the first security test is passed, the sender performs unitary transformations to encode the secret information on her particles and sends to the receiver. The receiver then performs projective measurements to decode the secret information. It enables the sender to transmit six-bit classical secret message by sending three particles to the receiver. The second security test is adopted to guarantee the security of the communication.
NANOSTRUCTURED Si/ZrO2 MESOPOROUS COMPOSITE FILM ANODES FOR LITHIUM ION BATTERIES
Authors: WANG X. L. , TU J. P. , XIANG J. Y. , HUANG X. H.
Published: April 2009

Mesoporous ZrO 2 with pore sizes of 5–20 nm were prepared using various structure-directing agents. Nanoscale Si was combined with mesoporous ZrO 2 to be used as anodes for lithium ion batteries. In the range of the Si / ZrO 2 mole ratio from 1:1 to 6:1, electrochemical investigations indicated that the mesoporous composite film with the mole ratio of 4:1 had larger capacity and better cyclability upon cycling. Its discharge capacity preserved 1251 mAh/g after 50 cycles. It is believed that mesoporous ZrO 2 could effectively alleviate the volume change arising from Li – Si alloying during the lithiation/delithiation process and provided channels with its mesopores for lithium ions passing through. The Si / ZrO 2 composite film with a pore size of 20 nm presented the best electrochemical performance, indicating that the larger mesopores could facilitate insertion/removal of lithium ions.
Rethinking signal processing
Authors: Kroeker Kirk L.
Published: April 2009

Compressed sensing, which draws on information theory, probability theory, and other fields, has generated a great deal of excitement with its nontraditional approach to signal processing.
Matchmaker, matchmaker
Authors: Essex David
Published: April 2009

Computational advertising seeks to place the best ad in the best context before the right customer.
Economic and business dimensionsIncreasing gender diversity in the IT work force
Authors: Coder LeAnne , Rosenbloom Joshua L , Ash Ronald A. , Dupont Brandon R.
Published: April 2009

Want to increase participation of women in IT work? Change the work.
Security in the browser
Authors: Wadlow Thomas , Gorelik Vlad
Published: April 2009

What can be done to make Web browsers secure while preserving their usability?
Dynamic heterogeneity and the need for multicore virtualization
Authors: Wells Philip M. , Chakraborty Koushik , Sohi Gurindar S.
Published: April 2009

As the computing industry enters the multicore era, exponential growth in the number of transistors on a chip continues to present challenges and opportunities for computer architects and system designers. We examine one emerging issue in particular: that of dynamic heterogeneity, which can arise, even among physically homogeneous cores, from changing reliability, power, or thermal conditions, different cache and TLB contents, or changing resource configurations. This heterogeneity results in a constantly varying pool of hardware resources, which greatly complicates software's traditional task of assigning computation to cores. In part to address dynamic heterogeneity, we argue that hardware should take a more active role in the management of its computation resources. We propose hardware techniques to virtualize the cores of a multicore processor, allowing hardware to flexibly reassign the virtual processors that are exposed, even to a single operating system, to any subset of the physical cores. We show that multicore virtualization operates with minimal overhead, and that it enables several novel resource management applications for improving both performance and reliability.
Runtime monitoring on multicores via OASES
Authors: Nagarajan Vijay , Gupta Rajiv
Published: April 2009

Runtime monitoring support serves as a foundation for the important tasks of providing security, performing debugging, and improving performance of applications. Often runtime monitoring requires the maintenance of information associated with each of the application's original memory location, which is held in corresponding shadow memory locations. Unfortunately, existing robust shadow memory implementations are inefficient. In this paper, we present OASES: OS and Architectural Support for Efficient Shadow memory implementation for multicores that is also robust. A combination of operating system support (in the form of coupled allocation of memory pages used by the application and associated shadow memory pages) and architectural support (in the form of ISA support and exposed cache events) is proposed. Our page allocation policy enables fast translation of original addresses into corresponding shadow memory addresses; thus allowing implicit addressing of shadow memory. By exposing the cache events to the software, we ensure in software that the shadow memory instructions execute atomically with their corresponding original memory instructions. Our experiments show that the overheads of runtime monitoring tasks are significantly reduced in comparison to previous software implementations.
Supporting MapReduce on large-scale asymmetric multi-core clusters
Authors: Rafique M. Mustafa , Rose Benjamin , Butt Ali R. , Nikolopoulos Dimitrios S.
Published: April 2009

Asymmetric multi-core processors (AMPs) with general-purpose and specialized cores packaged on the same chip, are emerging as a leading paradigm for high-end computing. A large body of existing research explores the use of standalone AMPs in computationally challenging and data-intensive applications. AMPs are rapidly deployed as high-performance accelerators on clusters. In these settings, scheduling, communication and I/O are managed by generalpurpose processors (GPPs), while computation is off-loaded to AMPs. Design space exploration for the configuration and software stack of hybrid clusters of AMPs and GPPs is an open problem. In this paper, we explore this design space in an implementation of the popular MapReduce programming model. Our contributions are: An exploration of various design alternatives for hybrid asymmetric clusters of AMPs and GPPs; the adoption of a streaming approach to supporting MapReduce computations on clusters with asymmetric components; and adaptive schedulers that take into account individual component capabilities in asymmetric clusters. Throughout our design, we remove I/O bottlenecks, using double-buffering and asynchronous I/O. We present an evaluation of the design choices through experiments on a real cluster with MapReduce workloads of varying degrees of computation intensity. We find that in a cluster with resource-constrained and well-provisioned AMP accelerators, a streaming approach achieves 50.5% and 73.1% better performance compared to the non-streaming approach, respectively, and scales almost linearly with increasing number of compute nodes.We also show that our dynamic scheduling mechanisms adapt effectively the parameters of the scheduling policies between applications with different computation density.
HASS
Authors: Shelepov Daniel , Saez Alcaide Juan Carlos , Jeffery Stacey , Fedorova Alexandra , Perez Nestor , Huang Zhi Feng , Blagodurov Sergey , Kumar Viren
Published: April 2009

Future heterogeneous single-ISA multicore processors will have an edge in potential performance per watt over comparable homogeneous processors. To fully tap into that potential, the OS scheduler needs to be heterogeneity-aware, so it can match jobs to cores according to characteristics of both. We propose a Heterogeneity-Aware Signature-Supported scheduling algorithm that does the matching using per-thread architectural signatures, which are compact summaries of threads' architectural properties collected offline. The resulting algorithm does not rely on dynamic profiling, and is comparatively simple and scalable. We implemented HASS in OpenSolaris, and achieved average workload speedups of up to 13%, matching best static assignment, achievable only by an oracle. We have also implemented a dynamic IPC-driven algorithm proposed earlier that relies on online profiling. We found that the complexity, load imbalance and associated performance degradation resulting from dynamic profiling are significant challenges to using this algorithm successfully. As a result it failed to deliver expected performance gains and to outperform HASS.
HTM design spaces
Authors: Kunal K. , George K. , Gautam M. , Kamakoti V.
Published: April 2009

This paper proposes a Hardware Transactional Memory (HTM) design for multi-core environments. Using a novel technique to keep track of transactional read-write entries, the design provides a holistic and scalable solution to Transactional Memory (TM) implementation issues of context switching, process migration and overflow handling. Another aspect of the design is that it allows transactions to run in a highly concurrent manner by using special techniques to handle conflict resolution, conflict detection and overflows. The feasibility and validity of the proposed design are demonstrated by developing a synthesizable Hardware Description Language (HDL) model of the design and also experimenting on the same with standard benchmarks.
Multicore diversity
Authors: Penry David A.
Published: April 2009

Commodity microprocessors with tens to hundreds of processor cores will require the widespread deployment of parallel programs. This deployment will be hindered by the architectural and environmental diversity introduced by multicore processors. To overcome diversity, the operating system must change its interactions with the program runtime and parallel runtime systems must be developed that can automatically adapt programs to the architecture and usage environment.
Conference reviewing considered harmful
Authors: Anderson Thomas
Published: April 2009

This paper develops a model of computer systems research to help prospective authors understand the often obscure workings of conference program committees. We present data to show that the variability between reviewers is often the dominant factor as to whether a paper is accepted. We argue that paper merit is likely to be zipf distributed, making it inherently difficult for program committees to distinguish between most papers. We use game theory to show that with noisy reviews and zipf merit, authors have an incentive to submit papers too early and too often. These factors make conference reviewing, and systems research as a whole, less efficient and less effective. We describe some recent changes in conference design to address these issues, and we suggest some further potential improvements.
From the chair
Authors: Sipior Janice C. , Lending Diane , Amoroso Donald L. , Shayo Conrad , Vowels Susan A.
Published: April 2009

The ACM-SIGMIS CPR (Computer Personnel Research) 2009 Conference and Doctoral Student Consortium is almost upon us! The University of Limerick campus in beautiful Limerick, Ireland is the location of this year's conference from May 28-30, 2009. Please check out our 2009 SIGMIS CPR BLOG at: http://sigmiscpr2009.blogspot.com to obtain travel, housing, and other information! Ask a question or post something you found!

Please plan to attend the annual SIGMIS Business Meeting to be held right at the close of the conference on Saturday, May 30, 2009. All are welcome!

Plans for next year's CPR 2010 Conference, to be held in Vancouver, BC, Canada, are now underway. The Conference Chair is Mike Gallivan, Georgia State University, mikegallivan@yahoo.com or mgallivan@gsu.edu. Please consider joining the program committee, participating in conference planning, and, of course, submitting your research by the October 2009 deadline. Encourage your colleagues to participate!

Remember to consult the ACM Digital Library at: http://portal.acm.org/dl.cfm to for this year's forthcoming CPR conference proceedings and Data Base articles. Referring to these publication outlets will keep you up-to-date and in touch with your colleagues' most recent research!

I encourage you to continue to submit your best work to Data Base. This publication is the primary vehicle of communication to our membership, presenting articles of practical research significance and relating experiences in the area of business uses of information systems. Data Base provides an accessible, flexible, and timely forum for information on both well-researched topics and those less common, perhaps leading-edge topics which may not yet have found their way into the literature. Controversial or untested research topics are welcome. Submission information is available at the Data Base website at: http://the-database.org.

As always, thanks for your continued support of SIGMIS. Please do contact any one of us with comments, ideas, and suggestions for improvement. Have a nice summer!

We look forward to seeing you at CPR'09!
Common input devices for Malaysian computer users with motor impairments
Authors: Hassan Hasni
Published: April 2009

This research aims to investigate whether there are common input devices that are more effective than a standard mouse for Malaysian computer users with motor impairment. The tasks range from very controlled Simple Reaction Time (SRT) tasks to Fitts' Law and browsing tasks. There are several potential contributions of the research beyond finding the input device that is more effective than a mouse: 1) The Fitts' Law model and information architecture for people with motor impairment and 2) the relationship between subjective and objective measures in highly controlled as well as naturalistic tasks.
A study of sign language coarticulation
Authors: Segouat Jérémie
Published: April 2009

This paper presents a coarticulation-modeling project in French Sign Language (LSF). We briefly introduce what sign language is about and why we study a specific part of it: to coarticulate isolated signs in order to create parameterized utterances. Then we explain what coarticulation means and how it has been studied in several research fields. We describe the methodology we have set up to reach our goal: creation of sign corpora, annotations of these corpora, analysis of these annotations, and finally design of a coarticulation model. The evaluation process will be made by different kind of people in various pieces of software.
Context-enhanced interaction techniques for more accessible mobile phones
Authors: Kane Shaun K.
Published: April 2009

Modern mobile phones enable users to access a wide variety of information and communication services anytime and anywhere. In order for people with disabilities to benefit from these services, mobile devices must provide accessible user interfaces. Currently, users with motor and visual impairments often have difficulty using mobile devices due to issues such as screen readability and small controls. These problems may be exacerbated when attempting to use such devices in crowded, noisy or otherwise distracting environments. We are developing accessible mobile interaction techniques that adapt the mobile device interface to the user by leveraging information about the user's current location, activity, and level of ability.
ICT-related skills and needs of blind and visually impaired people
Authors: van Puffelen Carolina
Published: April 2009

This study focuses on the relationship between the ICT-related training offered to blind and visually impaired people and their actual, self-reported and demonstrated, competencies for online activities and information processing. The findings of the study can shed light on how people with severe visual disabilities are prepared to access the web for educational, institutional and social participation. The study also gives insight in the validity of instruments to measure ICT-linked skills for the target group and creates an empirical foundation for improvements of ICT-related training. The first phase of the study investigated how blind and visually impaired people perceive their participation in society through ICT. An extensive interview showed how this audience perceives the frequency and quality of their Internet use (or absence thereof) and how they acquired these skills.
Thermodynamics and Mass Transport in Multicomponent, Multiphase H2O Systems of Planetary Interest
Authors: Lu Xinli , Kieffer Susan W.
Published: April 2009

Heat and mass transport in low-temperature, low-pressure H2O systems are important processes on Earth, and on a number of planets and moons in the Solar System. In most occurrences, these systems will contain other components, the so-called noncondensible gases, such as CO2, CO, SO2, CH4, and N2. The presence of the noncondensible components can greatly alter the thermodynamic properties of the phases and their flow properties as they move in and on the planets. We review various forms of phase diagrams that give information about pressure-temperature-volume-entropy-enthalpy-composition conditions in these complex systems. Fluid dynamic models must be coupled to the thermodynamics to accurately describe flow in gas-driven liquid and solid systems. The concepts are illustrated in detail by considering flow and flow instabilities such as geysering in modern geothermal systems on Earth, paleofluid systems on Mars, and cryogenic ice-gas systems on Mars and Enceladus. We emphasize that consideration of single-component end-member systems often leads to conclusions that exclude many qualitatively and quantitatively important phenomena.
The Tropics in Paleoclimate
Authors: Chiang John C.H.
Published: April 2009

The past decade saw a surge in interest in the role of the Tropics in paleoclimate changes. This was motivated by the emergence of outstanding questions in paleoclimate that pointed to a role for the Tropics in addition to advances in tropical climate dynamics. This article reviews these developments, starting from a historical perspective. Three properties of tropical dynamics are prominent in paleoclimate: the sensitivity of the tropical climate to change; the ability of the tropical climate to reorganize; and the ability of the tropical climate to project its influence globally. The El Niño-Southern Oscillation (ENSO) system exemplifies these properties, making ENSO particularly prominent in paleoclimate. Summaries of three paleoclimate cases in which the science developed over the past decade—mid-Holocene ENSO, abrupt climate change during the most recent glacial period, and the mid-Pliocene permanent El Niño scenario—illustrate how the tropical hypothesis worked its way into paleoclimate research. This review closes with a discussion of prevailing views of the Tropics in the paleoclimate changes.
Ten-Year Survival in 75-Year-Old Men and Women: Predictive Ability of Total Cholesterol, HDL-C, and LDL-C
Authors: Nilsson Göran , Öhrvik John , Lönnberg Ingemar , Hedberg Pär
Published: April 2009

Objective. The purpose of this study was to investigate prognostic impact of cholesterol and its subfractions among 75-year-old people from the general population.Methods and Results. The study comprised a random sample (222 women and 210 men) from the general population (participation rate 70%). During 10-year follow-up, 19% of women and 35% of men experienced a major cardiovascular event (MCVE). The all-cause mortality was 29% for women and 47% for men. After adjustment for cardiovascular risk factors, a low level of high-density lipoprotein cholesterol (HDL-C) was significantly associated with MCVE (P=.006) and mortality (P=.011) in men but not in women. The prognostic sex disparity was nearly significant (P=.051for MCVE and .067 for mortality). The associations of adjusted HDL-C to MCVE and mortality were unchanged after excluding individuals with prevalent stroke or MI. Total cholesterol and low-density lipoprotein cholesterol (LDL-C) were not significantly related to prognosis in either sex.Main Conclusions. HDL-C was associated with dismal prognosis in men but not in women. Elderly men with HDL-C  <40 mg/dL deserve particular attention for cardiovascular prevention.
Syndromes cholestatiques familiaux
Authors: Thompson Richard
Published: April 2009

Le terme «familial» est malheureux. Bien que la définition implique «héréditaire», elle sous-entend que l’affection est habituellement survenue chez d’autres membres de la famille. Pour un grand nombre des affections décrites dans le présent article, il n’en est souvent pas le cas, et, pour cette raison, des affections «familiales» peuvent être ignorées lors de la démarche diagnostique. La cholestase est définie de façon différente par les cliniciens, les anatomopathologistes et les biochimistes. De plus, la définition d’une hépatopathie cholestatique varie très souvent pour les hépatologues traitant des enfants ou des adultes. Les mécanismes pathogènes sont cependant de plus en plus similaires. L’atrésie des voies biliaires, qui est l’hépatopathie cholestatique à laquelle les pédiatres sont le plus souvent confrontés, est nettement différente de la plupart des maladies car il paraît n’exister aucun équivalent à «début tardif», et car cette affection n’est quasiment jamais familiale. Plusieurs groupes coopératifs internationaux ont été constitués dans l’espoir de surmonter ces obstacles (http://www.barcnetwork.org/, http://www.orpha.net/nestasso/EFBAR/, http://www.biliary- atresia.com/index_frameset_ebar.html). Dans sa pratique quotidienne, l’hépatologue pédiatre est confronté à un groupe de nourrissons ictériques chez qui la cause n’est pas facilement apparente. Sous de nombreux aspects, cette situation a été aggravée par le fait, que nous savions depuis longtemps qu’une proportion significative s’améliorera spontanément, tandis que l’évolution sera défavorable chez d’autres patients. Au cours des premiers mois de la vie, il demeure difficile de prévoir l’évolution chez un patient donné. La cause sous-jacente, au moins dans le groupe dont l’évolution est péjorative, devient apparente dans un nombre de plus en plus important de cas. La plus grande partie des améliorations des possibilités diagnostiques dans ce groupe d’enfants est la conséquence de progrès des connaissances de l’étiologie génétique. Il est également devenu manifeste que l’hépatopathie cholestatique d’origine génétique n’est pas limitée à la population pédiatrique. L’étendue précise de la contribution de facteurs génétiques à l’apparition d’une forme à «début tardif» commence seulement à être mieux connue.
Basal and Oxidative Stress–Induced Expression of Metallothionein Is Decreased in Ascending Aortic Aneurysms of Bicuspid Aortic Valve Patients
Authors: Phillippi Julie A. , Klyachko Ekaterina A. , Kenny John P. , Eskay Michael A. , Gorman Robert C. , Gleason Thomas G.
Published: April 2009

Background—

Bicuspid aortic valve (BAV) is a heritable condition that has been linked by an unknown mechanism to a predisposition for ascending aortic aneurysm. Matrix metalloproteinases have been implicated in this predisposition. Metallothionein is a poorly characterized, metal-binding protein that regulates matrix metalloproteinases and is an antioxidant known to be upregulated under oxidative stress.

Methods and Results—

To determine putative factors involved in the pathogenesis of aortic aneurysm in BAV patients, our first goal was to identify genes that are dysregulated in ascending aortic aneurysms of BAV patients compared with tricuspid aortic valve patients and nondiseased (control) donors. By microarray analysis (22 000 probe sets), 110 dysregulated genes were identified in BAV compared with tricuspid aortic valve patients and control donors; 8 were genes of the metallothionein family. Metallothionein gene expression and protein expression were significantly lower in aortic tissue and cultured aortic smooth muscle cells from BAV patients compared with control subjects. Matrix metalloproteinase-9 expression was increased in BAV aortic samples relative to controls. BAV aorta was more susceptible to oxidative stress, and induction of metallothionein under oxidative stress was reduced in BAV patients compared with control subjects.

Conclusions—

These results demonstrate dysregulated metallothionein expression in ascending aortic smooth muscle cells of BAV patients that may contribute to an inadequate response to oxidative stress and provoke aneurysm formation. We hypothesize that metallothionein plays a pivotal role in the response of ascending aortic smooth muscle cells to oxidative stress cues normally involved in the maintenance of the extracellular matrix, including the regulation of matrix metalloproteinase expression.
MTHFR
677 C>T Polymorphism Reveals Functional Importance for 5-Methyltetrahydrofolate, Not Homocysteine, in Regulation of Vascular Redox State and Endothelial Function in Human Atherosclerosis
Authors: Antoniades Charalambos , Shirodaria Cheerag , Leeson Paul , Baarholm Otto A. , Van-Assche Tim , Cunnington Colin , Pillai Ravi , Ratnatunga Chandi , Tousoulis Dimitris , Stefanadis Christodoulos , Refsum Helga , Channon Keith M.
Published: April 2009

Background—

The role of circulating homocysteine as an atherosclerosis risk factor has recently been questioned. However, 5-methyl-tetrahydrofolate (5-MTHF), the circulating metabolite of folic acid participating in homocysteine metabolism, has direct effects on vascular function. We sought to distinguish the effects of plasma versus vascular tissue 5-MTHF and homocysteine on vascular redox and endothelial nitric oxide bioavailability in human vessels.

Methods and Results—

We used the methyl tetrahydrofolate reductase (
MTHFR
) gene polymorphism 677C>T as a model of chronic exposure of the vascular wall to varying 5-MTHF levels in 218 patients undergoing coronary artery bypass graft surgery. Vascular superoxide, vascular 5-MTHF, and total homocysteine were determined in saphenous veins and internal mammary arteries obtained during surgery. Nitric oxide bioavailability was evaluated by organ bath studies on saphenous vein rings. MTHFR genotype was a determinant of vascular 5-MTHF (not vascular homocysteine). Both MTHFR genotype and vascular 5-MTHF were associated with vascular nitric oxide bioavailability and superoxide generated by uncoupled endothelial nitric oxide synthase. In contrast, vascular homocysteine was associated only with NADPH-stimulated superoxide.

Conclusions—

Genetic polymorphism 677 C>T on
MTHFR
affects vascular 5-MTHF (but not homocysteine) and can be used as a model to distinguish the chronic effects of vascular 5-MTHF from homocysteine on vascular wall. Vascular 5-MTHF, rather than plasma or vascular homocysteine, is a key regulator of endothelial nitric oxide synthase coupling and nitric oxide bioavailability in human vessels, suggesting that plasma homocysteine is an indirect marker of 5-MTHF rather than a primary regulator of endothelial function.
Extracellular Cardiac Matrix Biomarkers in Patients With Acute Myocardial Infarction Complicated by Left Ventricular Dysfunction and Heart Failure
Authors: Iraqi Wafae , Rossignol Patrick , Angioi Michael , Fay Renaud , Nuée Josette , Ketelslegers Jean Marie , Vincent John , Pitt Bertram , Zannad Faiez
Published: April 2009

Background—

Aldosterone stimulates cardiac collagen synthesis. Circulating biomarkers of collagen turnover provide a useful tool for the assessment of cardiac remodeling in patients with congestive heart failure and left ventricular systolic dysfunction after acute myocardial infarction.

Methods and Results—

In a substudy of the Eplerenone Post–Acute Myocardial Infarction Heart Failure Efficacy and Survival Study (EPHESUS), which evaluated the effects of the selective aldosterone receptor antagonist eplerenone versus placebo, serum levels of collagen biomarkers were measured in 476 patients with congestive heart failure after acute myocardial infarction complicated with left ventricular systolic dysfunction. The combination of the type I collagen telopeptide and brain natriuretic peptide levels above median at baseline was associated with all-cause mortality and the composite end point of cardiovascular death or heart failure hospitalization, with hazard ratios of 2.49 (
P
=0.039) and 3.03 (
P
=0.002), respectively. During follow-up, levels of aminoterminal propeptide of type I and type III procollagen were found to be consistently lower in the eplerenone group and significantly lower beginning at 6 months.

Conclusions—

Changes in biomarkers of collagen synthesis and degradation suggest that extracellular matrix remodeling is an active process in patients with congestive heart failure and left ventricular systolic dysfunction after acute myocardial infarction. High type I collagen telopeptide and high brain natriuretic peptide serum levels are associated with the highest event rate. Eplerenone suppresses post–acute myocardial infarction collagen turnover changes.
Endothelial Epithelial Sodium Channel Inhibition Activates Endothelial Nitric Oxide Synthase via Phosphoinositide 3-Kinase/Akt in Small-Diameter Mesenteric Arteries
Authors: Pérez Francisco R. , Venegas Fabiola , González Magdalena , Andrés Sergio , Vallejos Catalina , Riquelme Gloria , Sierralta Jimena , Michea Luis
Published: April 2009

Recent studies have shown that the epithelial sodium channel (ENaC) is expressed in vascular tissue. However, the role that ENaC may play in the responses to vasoconstrictors and NO production has yet to be addressed. In this study, the contractile responses of perfused pressurized small-diameter rat mesenteric arteries to phenylephrine and serotonin were reduced by ENaC blockade with amiloride (75.1±3.2% and 16.9±2.3% of control values, respectively;
P
<0.01) that was dose dependent (EC
50
=88.9±1.6 nmol/L). Incubation with benzamil, another ENaC blocker, had similar effects. α, β, and γ ENaC were identified in small-diameter rat mesenteric arteries using RT-PCR and Western blot with specific antibodies. In situ hybridization and immunohistochemistry localized ENaC expression to the
tunica media
and endothelium of small-diameter rat mesenteric arteries. Patch-clamp experiments demonstrated that primary cultures of mesenteric artery endothelial cells expressed amiloride-sensitive sodium currents. Mechanical ablation of the endothelium or inhibition of eNOS with
N
ω
-nitro-
l
-arginine inhibited the reduction in contractility caused by ENaC blockers. ENaC inhibitors increased eNOS phosphorylation (Ser 1177) and Akt phosphorylation (Ser 473). The presence of the phosphoinositide 3-kinase inhibitor LY294002 blunted Akt phosphorylation and eNOS phosphorylation and the decrease in the response to phenylephrine caused by blockers of ENaC, indicating that the phosphoinositide 3-kinase/Akt pathway was activated after ENaC inhibition. Finally, we observed that the effects of blockers of ENaC were flow dependent and that the vasodilatory response to shear stress was enhanced by ENaC blockade. Our results identify a previously unappreciated role for ENaC as a negative modulator of eNOS and NO production in resistance arteries.