bluuebunny/crossref_metadata_2025 huggingface dataset:
Muscle fatigue resistance during stimulated contractions is reduced in young male smokers
Authors: Morse C. I. , Wüst R. C. I. , Jones D. A. , De Haan A. , Degens H.
Published: June 2007

Aim:  To determine whether muscle function is compromised in healthy smokers in comparison with activity‐matched non‐smokers.

Methods:  Nine male smokers (aged 22.2 ± 2.5 years: mean ± SD) with a smoking history of 2.5 ± 3.1 pack years, and ten male control participants (25.4 ± 2.9 years) matched for physical activity level participated in this study. Knee extensor strength was measured using isometric maximal voluntary contractions. Voluntary activation of the quadriceps and co‐activation of the biceps femoris were determined using interpolated twitches and surface electromyography respectively. The frequency–torque relationship and fatigue resistance were assessed with electrically evoked contractions. A fatigue index was determined as the ratio of final torque to initial torque during a series of isometric contractions (2 min; 30 Hz; 1 s contraction/1 s rest). Quadriceps anatomical cross sectional area was measured with MRI at 50% of femur length.

Results:  Maximal voluntary contraction torque, quadriceps anatomical cross sectional area, knee extensor torque/quadriceps cross sectional area, activation, co‐activation and force–frequency relationship were similar, whereas the fatigue index was 17% lower in smokers than non‐smokers.

Conclusion:  In young men smoking does not significantly affect quadriceps muscle mass and contractile properties, but does reduce fatigue resistance of the quadriceps muscle, which was not attributable to differences in physical activity.
Models of mental health care for older adults: a review of the literature
Authors: Moyle Wendy , Evans Katie
Published: June 2007

Aim. This paper reviews literature that draws on models of mental health care for older adults.

Background. It is predicted that as a consequence of the aging of the population the incidence of mental health disorders, common in older populations, will also rise. Many such disorders can be successfully managed if detected early. Assessment and management requires collaboration between health professionals who are skilled and educated in the management of older adults with mental illness and the use of models of care appropriate to this population.

Results. The paucity of research in this area is demonstrated.

Conclusion. The need for mental health nurses to challenge current models of mental health care for older adults is identified so that they take on an expanded and developed specialist role in care of older adults with mental illness.
A needs‐based model for older people's mental health
Authors: Mander Paul
Published: June 2007

Abstract  Background.  Mental health services for older people in South Tyneside (UK) have adopted a person‐centred service model that is ‘needs‐led’. This service model uses Local Authority ‘Fair Access to Care Services’ (FACS) eligibility criteria to ensure fair and equal access to mental health services for older people in South Tyneside based upon their level of mental health need. This is achieved by the application of mental health specific criteria within the FACS framework.

Aims.  This paper describes how stakeholders from statutory and non‐statutory organizations in South Tyneside, in consultation with service users and carers, collaborated to produce the model and the application into practice of the model. Furthermore, the development of specific indicators of level of mental health needs supplementary to FACS, as commonly shared and understood language across boundaries is described.

Conclusions.  The model is argued as the basis for collaboration and empowerment of practitioners across organizations to drive and lead positive change and is an essential and appropriate framework for the commissioning of services in addition to ensuring the appropriate and timely provision of needs‐led services for older people with mental health needs.
Discharge of the older person from the emergency department – the perceptions of health professionals
Authors: Dunnion Mary E. , Kelly Billy
Published: June 2007

Aims of study.  This study aimed to examine the management of the older person in preparation for discharge home from an emergency department by exploring the perceptions of health professionals on procedures undertaken particularly in relation to the planned support, supply of medications, dressings, and contact information given to patients. An additional aim related to the perceived satisfaction levels of older patients and their carers.

Background.  It is imperative that older patients are adequately prepared for discharge home from the emergency department so as to avoid unnecessary anxiety, increase in health problems and possible re‐attendance or admission to hospital.

Design.  The sample in this study comprised the total population (n = 222) of all medical and nursing staff in both the emergency department and the primary care area.

Methods.  The method adopted was a survey approach which employed the use of standardized questionnaires comprising both open and closed questioning styles.

Results.  The data obtained identified results similar to previous research in that a discrepancy exists between hospital and community staff in relation to the procedures undertaken when discharging older people from the emergency department, such as arranging follow‐up care and appointments and giving the patient relevant contact numbers and dressings.

Conclusion.  The findings of this study support previous research in that there is a need to provide patients with planned support, aids and appliances, clear instructions and relevant contact numbers on discharge from the emergency department.

Relevance to clinical practice.  Good quality discharge planning is essential for a continuum of care for older people discharged from the emergency department. While patient education is often difficult in the busy emergency department, the provision of relevant information to older patients prior to discharge is essential particularly in relation to prescribed medications and wound care.
How Has Rural Tax Reform Affected Farmers and Local Governance in China?
Authors: Tao Ran , Qin Ping
Published: June 2007

Using nationally representative data, the present paper examines the impact of China's ongoing rural tax reform on farmers. The difficulties in further local governance restructuring are also discussed. It is argued that the issues associated with rural taxation and local governance in China result from inherent tension between an increasingly liberalized economic system and a still centralized political system. Although rural tax reform has helped to reduce farmers' tax burdens in the short term, the establishment of an effective local governance regime requires coordinated reforms to downsize local bureaucracy by providing social security for laid‐off cadres, to strengthen local accountability by granting higher local formal tax autonomy, and to promote meaningful participation by expanding local democracy.
China's Industrial Policy in Relation to Electronics Manufacturing
Authors: Zhao Zhongxiu , Huang Xiaoling , Ye Dongya , Gentle Paul
Published: June 2007

China has become the biggest exporter of electronic products in the world. Government policy intervention has contributed significantly to the rapid expansion of the electronics industry. The present paper examines the evolutionary development of industrial policies related to the electronics industry in China and the impacts of such policies on the shaping of the industry. In particular, the relationship between foreign funded enterprises and domestic firms are examined in detail. The future trend of the industry is also discussed in the paper, and the policy focus of the Chinese Government is predicted.
Multiple Forces Driving China's Economic Development: A New Analytic Framework
Authors: Wang Yahua , Hu Angang
Published: June 2007

Based on economic growth theory and the World Bank's analytical framework relating to the quality of growth, the present paper constructs a framework that encompasses physical, international, human, natural and knowledge capital to synthetically interpret economic development. After defining the five types of capital and total capital, we analyze the dynamic changes of these types of capital in China and in other countries. The results show that since China's reform and opening up, knowledge, international, human and physical capital have grown rapidly, with speeds of growth higher than that of economic growth. As the five types of capital have all increased at varying paces, the savings level of total capital in China has quadrupled in 25 years and overtook that of the USA in the 1990s. The changes in the five types of capital and total capital reveal that there are progressively multiple driving forces behind China's rapid economic development. Implications for China's long‐term economic development are thereby raised.
Applications of Chitosan for Improvement of Quality and Shelf Life of Foods: A Review
Authors: No H.K. , Meyers S.P. , Prinyawiwatkul W. , Xu Z.
Published: June 2007

ABSTRACT: Chitosan is a modified, natural biopolymer derived by deacetylation of chitin, a major component of the shells of crustacean. Recently, chitosan has received increased attention for its commercial applications in the biomedical, food, and chemical industries. Use of chitosan in food industry is readily seen due to its several distinctive biological activities and functional properties. The antimicrobial activity and film‐forming property of chitosan make it a potential source of food preservative or coating material of natural origin. This review focuses on the applications of chitosan for improvement of quality and shelf life of various foods from agriculture, poultry, and seafood origin.
Effect of Water Phase Salt Content and Storage Temperature on Listeria monocytogenes Survival in Chum Salmon (Oncorhynchus keta) Roe and Caviar (Ikura)
Authors: Shin Joong‐Han , Rasco Barbara A.
Published: June 2007

ABSTRACT:  Salmon caviar, or ikura, is a ready‐to‐eat food prepared by curing the salmon roe in a brine solution. Other seasonings or flavorants may be added, depending upon the characteristics of the product desired. Listeria monocytogenes growth is a potential risk, since it can grow at high salt concentrations (>10%) and in some products at temperatures as low as 3 °C. Ikura was prepared from chum salmon (Oncorhynchus keta) roe by adding food‐grade NaCl to yield water phase salt contents (WPS) of 0.22% (no added salt), 2.39%± 0.18%, 3.50%± 0.19%, and 4.36%± 0.36%. A cocktail containing L. monocytogenes (ATCC 19114, 7644, 19113) was incorporated into the ikura at 2 inoculum levels (log 2.4 and 4.2 CFU/g), and stored at 3 or 7 °C for up to 30 d. L. monocytogenes was recovered by plating onto modified Oxford media. Aerobic microflora were analyzed on plate count agar. Samples were tested at 0, 5, 10, 20, and 30 d. L. monocytogenes did not grow in chum salmon ikura held at 3 °C during 30 d at any salt level tested; however, the addition of salt at these levels did little to inhibit Listeria growth at 7 °C and counts reached 5 to 6 logs CFU/g. Components in the salmon egg intracellular fluid appear to inhibit the growth of L. monocytogenes. Total aerobic microflora levels were slightly lower in products with higher salt contents. These results indicate that temperature control is critical for ikura and similar products, but that products with lower salt contents can be safe, as long as good refrigeration is maintained.
Surface Modification and Fatigue Behavior of High-Pressure Oil Jet-Peened Medium Carbon Steel, AISI 1040
Authors: Grinspan A. Sahaya , Gnanamoorthy R.
Published: June 2007

Introduction of compressive residual stresses on the fatigue-loaded components is one of the techniques followed to improve the fatigue life of industrial components. Oil jet peening is a surface modification process for the introduction of compressive residual stresses. A high-pressure oil jet is made to impinge on the surface to be peened. Preliminary studies were carried out on the medium carbon steel at the oil pressure of 50MPa. The compressive residual stress induced on the surface of unpeened and oil jet-peened AISI 1040 steel was 21MPa and 200MPa, respectively. Fully reversed cantilever bending fatigue behaviors of medium carbon steel in both under peened and unpeened conditions were evaluated at room temperature. Oil jet-peened specimens exhibited superior fatigue performance compared to the unpeened specimens. Fractographical analyses were carried out for specimens broken at several tested stress levels using optical microscope.
Variation Simulation of Sheet Metal Assemblies Using the Method of Influence Coefficients With Contact Modeling
Authors: Dahlström Stefan , Lindkvist Lars
Published: June 2007

Sheet metal assembly is a common assembly process for several products such as automobiles and airplanes. Since all manufacturing processes are affected by variation, and products need to have a high geometric quality, geometry-related production problems must be analyzed during early design phases. This paper discusses two methods of performing this analysis. One way of performing the simulations relatively fast is to establish linear relationships between part deviation and assembly springback deviation by using the method of influence coefficient (MIC). However, this method does not consider contact between the parts. This means that the parts are allowed to penetrate each other which can affect the accuracy of the simulation result. This paper presents a simple contact modeling technique that can be implemented in to MIC to avoid penetrations. The contact modeling consists of a contact detection and a contact equilibrium search algorithm. When implemented, MIC still only requires two finite element analysis (FEA) calculations. This paper describes the steps in the contact algorithm and how it can be used in MIC, and finally the proposed contact modeling is verified by comparing the simulation result with commercial FEA software ABAQUS contact algorithm.
Modeling of the Size Effects on the Behavior of Metals in Microscale Deformation Processes
Authors: Kim Gap-Yong , Ni Jun , Koç Muammer
Published: June 2007

For the accurate analysis and design of microforming process, proper modeling of material behavior at the micro/mesoscale is necessary by considering the size effects. Two size effects are known to exist in metallic materials. One is the “grain size” effect, and the other is the “feature/specimen size” effect. This study investigated the feature/specimen size effect and introduced a scaling model which combined both feature/specimen and grain size effects. Predicted size effects were compared with three separate experiments obtained from previous research: a simple compression with a round specimen, a simple tension with a round specimen, and a simple tension in sheet metal. The predicted results had a very good agreement with the experiments. Quantification of the miniaturization effect has been achieved by introducing two parameters, α and β, which can be determined by the scaling parameter n, to the Hall–Petch equation. The scaling model offers a simple way to model the size effect down to length scales of a couple of grains and to extend the use of continuum plasticity theories to micro/mesolength scales.
Lapping of Electrical Discharge Machining Processed Tool Steel Surface Using Elliptical Tool Motion
Authors: Mizuno Masahiro , Iyama Toshirou , Sugawara Susumu , Zhang Bi
Published: June 2007

A prototype lapping machine, which finishes surfaces by applying elliptical motions to a lapping tool in the presence of diamond compound, is developed. This paper describes the structure of the lapping machine, the 2-dimensional tool motions measured on the machine, the behavior of the diamond compounds between the tool and lapping surfaces, and the fundamental lapping performance. The tool motions are measured using a laser Doppler vibrometer and the proportional constants that are needed to obtain an objective tool motion are determined with the regression technique. The motion behavior of the diamond abrasive grains for each tool motion is directly observed with a microscope through a glass plate. Lapping experiments are conducted under the conditions with and without the work-feed. After lapping, the workpiece surface is measured using a surface profilometer for surface roughness and profile information. As a result, a surface roughness of less than 0.1μmRa is achieved using a 3μm compound and near-circular tool motion of 12.5μm radius.
Modeling Cutting: Plastic Deformation of Polymer Samples Indented With a Wedge
Authors: Meehan Richard R. , Burns S. J.
Published: June 2007

An experiment was designed to relate force to plastic deformation caused by a wedge indenting the edge surface of a polymer sample. The experiment reveals the primary phenomena observed in industrial converting processes of cutting and slitting of thin polymer films. The thin film was modeled using a polycarbonate rectangular block, which was indented with a metallic half-round wedge that represents the industrial cutter blades. The wedge radius and sample size were selected to scale to the ratio of slitting blade radius and industrial film thickness. A compression test frame impressed wedges into polymer samples with measurements of both force and displacement recorded. These experiments clearly revealed the shape of the plastic deformation zone ahead of and around the wedges. Data from the experiments showed increasing cutting force with wedge displacement until the sample fractured. Plastic deformation of the samples was examined: the out-of-plane plastic volume was shown to equal the volume displaced by the wedge. Cracks that developed from the side of the wedge tip during indention propagated with near steady-state loads under edge surface indention.
Thermo-Mechanical Finite Element Modeling of the Friction Drilling Process
Authors: Miller Scott F. , Shih Albert J.
Published: June 2007

Friction drilling uses a rotating conical tool to penetrate the workpiece and create a bushing in a single step without generating chips. This research investigates the three-dimensional (3D) finite element modeling (FEM) of large plastic strain and high-temperature work-material deformation in friction drilling. The explicit FEM code with temperature-dependent mechanical and thermal properties, as well as the adaptive meshing, element deletion, and mass scaling three FEM techniques necessary to enable the convergence of solution, is applied. An inverse method to match the measured and modeling thrust force determines a coefficient of friction of 0.7 in this study. The model is validated by comparing the thrust force, torque, and temperature to experimental measurements with reasonable accuracy. The FEM results show that the peak temperature of the workpiece approaches the work-material solidus temperature. Distributions of plastic strain, temperature, stress, and deformation demonstrate the thermomechanical behavior of the workpiece and advantages of 3D FEM to study of work-material deformation in friction drilling.
Natural Convection in a Partitioned Vertical Enclosure Heated With a Uniform Heat Flux
Authors: Kahveci Kamil
Published: June 2007

This numerical study looks at laminar natural convection in an enclosure divided by a partition with a finite thickness and conductivity. The enclosure is assumed to be heated using a uniform heat flux on a vertical wall, and cooled to a constant temperature on the opposite wall. The governing equations in the vorticity-stream function formulation are solved by employing a polynomial-based differential quadrature method. The results show that the presence of a vertical partition has a considerable effect on the circulation intensity, and therefore, the heat transfer characteristics across the enclosure. The average Nusselt number decreases with an increase of the distance between the hot wall and the partition. With a decrease in the thermal resistance of the partition, the average Nusselt number shows an increasing trend and a peak point is detected. If the thermal resistance of the partition further declines, the average Nusselt number begins to decrease asymptotically to a constant value. The partition thickness has little effect on the average Nusselt number.
Thermal Radiative Properties of a Semitransparent Fiber Coated With a Thin Absorbing Film
Authors: Tian Weixue , Huang Wei , Chiu Wilson K. S.
Published: June 2007

This study presents the hemispherical model to predict the hemispherical total thermal radiative properties of a fiber coated with a thin film. The fiber is composed of semi-transparent media, such as fused silica. The film is made of strong absorbing media with thickness on the order of tens of nanometers. The film is assumed to be “locally flat” at the point of incidence for radiative transfer analysis because the thickness of the film is much less than the fiber radius. Wave optics is employed to calculate the reflectance and transmittance of the thin film while the ray tracing method is used for radiative transport analysis of the fiber. Effects of film and fiber substrate optical properties, film thickness and temperature on predicted thermal radiative properties are investigated. One of the applications of the proposed model is for studying the chemical vapor deposition of hermetic coatings on optical fibers, in which the thermal radiative properties of the fiber–film system heavily influence the fiber surface temperature and chemical reaction rate.
Environmental Sensing and Signal Transduction Pathways Regulating Morphopathogenic Determinants of
Candida albicans
Authors: Biswas Subhrajit , Van Dijck Patrick , Datta Asis
Published: June 2007

Candida albicans
is an opportunistic fungal pathogen that is found in the normal gastrointestinal flora of most healthy humans. However, under certain environmental conditions, it can become a life-threatening pathogen. The shift from commensal organism to pathogen is often correlated with the capacity to undergo morphogenesis. Indeed, under certain conditions, including growth at ambient temperature, the presence of serum or
N
-acetylglucosamine, neutral pH, and nutrient starvation,
C. albicans
can undergo reversible transitions from the yeast form to the mycelial form. This morphological plasticity reflects the interplay of various signal transduction pathways, either stimulating or repressing hyphal formation. In this review, we provide an overview of the different sensing and signaling pathways involved in the morphogenesis and pathogenesis of
C. albicans
. Where appropriate, we compare the analogous pathways/genes in
Saccharomyces cerevisiae
in an attempt to highlight the evolution of the different components of the two organisms. The downstream components of these pathways, some of which may be interesting antifungal targets, are also discussed.
Role of Receptors in
Bacillus thuringiensis
Crystal Toxin Activity
Authors: Pigott Craig R. , Ellar David J.
Published: June 2007

Bacillus thuringiensis
produces crystalline protein inclusions with insecticidal or nematocidal properties. These crystal (Cry) proteins determine a particular strain's toxicity profile. Transgenic crops expressing one or more recombinant Cry toxins have become agriculturally important. Individual Cry toxins are usually toxic to only a few species within an order, and receptors on midgut epithelial cells have been shown to be critical determinants of Cry specificity. The best characterized of these receptors have been identified for lepidopterans, and two major receptor classes have emerged: the aminopeptidase N (APN) receptors and the cadherin-like receptors. Currently, 38 different APNs have been reported for 12 different lepidopterans. Each APN belongs to one of five groups that have unique structural features and Cry-binding properties. While 17 different APNs have been reported to bind to Cry toxins, only 2 have been shown to mediate toxin susceptibly in vivo. In contrast, several cadherin-like proteins bind to Cry toxins and confer toxin susceptibility in vitro, and disruption of the cadherin gene has been associated with toxin resistance. Nonetheless, only a small subset of the lepidopteran-specific Cry toxins has been shown to interact with cadherin-like proteins. This review analyzes the interactions between Cry toxins and their receptors, focusing on the identification and validation of receptors, the molecular basis for receptor recognition, the role of the receptor in resistant insects, and proposed models to explain the sequence of events at the cell surface by which receptor binding leads to cell death.
A Biochemical Guide to Yeast Adhesins: Glycoproteins for Social and Antisocial Occasions
Authors: Dranginis Anne M. , Rauceo Jason M. , Coronado Juan E. , Lipke Peter N.
Published: June 2007

Fungi are nonmotile eukaryotes that rely on their adhesins for selective interaction with the environment and with other fungal cells. Glycosylphosphatidylinositol (GPI)-cross-linked adhesins have essential roles in mating, colony morphology, host-pathogen interactions, and biofilm formation. We review the structure and binding properties of cell wall-bound adhesins of ascomycetous yeasts and relate them to their effects on cellular interactions, with particular emphasis on the agglutinins and flocculins of
Saccharomyces
and the Als proteins of
Candida
. These glycoproteins share common structural motifs tailored to surface activity and biological function. After being secreted to the outer face of the plasma membrane, they are covalently anchored in the wall through modified GPI anchors, with their binding domains elevated beyond the wall surface on highly glycosylated extended stalks. N-terminal globular domains bind peptide or sugar ligands, with between millimolar and nanomolar affinities. These affinities and the high density of adhesins and ligands at the cell surface determine microscopic and macroscopic characteristics of cell-cell associations. Central domains often include Thr-rich tandemly repeated sequences that are highly glycosylated. These domains potentiate cell-to-cell binding, but the molecular mechanism of such an association is not yet clear. These repeats also mediate recombination between repeats and between genes. The high levels of recombination and epigenetic regulation are sources of variation which enable the population to continually exploit new niches and resources.
Viral Proteomics
Authors: Maxwell Karen L. , Frappier Lori
Published: June 2007

Viruses have long been studied not only for their pathology and associated disease but also as model systems for molecular processes and as tools for identifying important cellular regulatory proteins and pathways. Recent advances in mass spectrometry methods coupled with the development of proteomic approaches have greatly facilitated the detection of virion components, protein interactions in infected cells, and virally induced changes in the cellular proteome, resulting in a more comprehensive understanding of viral infection. In addition, a rapidly increasing number of high-resolution structures for viral proteins have provided valuable information on the mechanism of action of these proteins as well as aided in the design and understanding of specific inhibitors that could be used in antiviral therapies. In this paper, we discuss proteomic studies conducted on all eukaryotic viruses and bacteriophages, covering virion composition, viral protein structures, virus-virus and virus-host protein interactions, and changes in the cellular proteome upon viral infection.
Risk of injury on artificial turf and natural grass in young female football players
Authors: Steffen Kathrin , Andersen Thor Einar , Bahr Roald
Published: June 2007

Background:Artificial turf is becoming increasingly popular, although the risk of injury on newer generations of turf is unknown.

Aim:To investigate the risk of injury on artificial turf compared with natural grass among young female football players.

Study design:Prospective cohort study.

Methods:2020 players from 109 teams (mean (SD) 15.4 (0.8) years) participated in the study during the 2005 football season. Time-loss injuries and exposure data on different types of turf were recorded over an eight-month period.

Results:421 (21%) players sustained 526 injuries, leading to an injury incidence of 3.7/1000 playing hours (95% CI 3.4 to 4.0). The incidence of acute injuries on artificial turf and grass did not differ significantly with respect to match injuries (rate ratio (RR) 1.0, 95% CI 0.8 to 1.3; p = 0.72) or training injuries (RR 1.0, 95% CI 0.6 to 1.5, p = 0.93). In matches, the incidence of serious injuries was significantly higher on artificial turf (RR 2.0, 95% CI 1.3 to 3.2; p = 0.03). Ankle sprain was the most common type of injury (34% of all acute injuries), and there was a trend towards more ankle sprains on artificial turf than on grass (RR 1.5, 95% CI 1.0 to 2.2; p = 0.06).

Conclusion:In the present study among young female football players, the overall risk of acute injuries was similar between artificial turf and natural grass.
ACTN3 genotype in professional soccer players
Authors: Santiago C , González-Freire M , Serratosa L , Morate F J , Meyer T , Gómez-Gallego F , Lucia A
Published: June 2007

The authors studied the frequency distribution of α-actinin-3 (ACTN3) R577X genotypes in 60 top-level professional soccer players. The results were compared with those of 52 elite endurance athletes and 123 sedentary controls. The per cent distribution of RR and RX genotypes in soccer players (48.3% and 36.7%) was significantly higher and lower, respectively, than controls (28.5% and 53.7%) and endurance athletes (26.5% and 52%) (p = 0.041). Although there are notable exceptions, elite soccer players tend to have the sprint/powerACTN3genotype.
BRST INVARIANCE OF NONLOCAL CHARGES AND MONODROMY MATRIX OF BOSONIC STRING ON AdS5×S5
Authors: KLUSOŇ J.
Published: June 2007

Using the generalized Hamiltonian method of Batalin, Fradkin and Vilkovsky we develop the BRST formalism for the bosonic string on AdS 5× S 5 formulated as principal chiral model. Then we show that the monodromy matrix and nonlocal charges are BRST invariant.
COSMOLOGY IN NONLINEAR BORN–INFELD SCALAR FIELD THEORY WITH NEGATIVE POTENTIALS
Authors: FANG WEI , LU H. Q. , HUANG Z. G.
Published: June 2007

The cosmological evolution in Nonlinear Born–Infeld (hereafter NLBI) scalar field theory with negative potentials was investigated. The cosmological solutions in some important evolutive epoches were obtained. The different evolutional behaviors between NLBI and linear (canonical) scalar field theory have been presented. A notable characteristic is that NLBI scalar field behaves as ordinary matter nearly the singularity while the linear scalar field behaves as "stiff" matter. We find that in order to accommodate current observational accelerating expanding universe the value of potential parameters |m| and |V0| must have an upper bound. We compare different cosmological evolutions for different potential parameters m, V0.
A deterministic logical semantics for pure Esterel
Authors: Tardieu Olivier
Published: June 2007

Esterel is a synchronous design language for the specification of reactive systems. There exist two main semantics for Esterel. On the one hand, the logical behavioral semantics provides a simple and compact formalization of the behavior of programs using SOS rules. But it does not ensure deterministic deadlock-free executions, as it may define zero, one, or many possible behaviors for a given program and input sequence. Since nondeterministic programs have to be rejected by compilers, this means that it defines behaviors for incorrect programs, which is awkward. On the other hand, the constructive semantics is deterministic (amongst other properties) but at the expense of a much more complex formalism. In this work, we build and thoroughly analyze a new deterministic semantics for Esterel that retains the simplicity of the logical behavioral semantics from which it derives. It defines, at most, one behavior per program and input sequence. We further extend this semantics with the ability to deal with errors so that incorrect programs are no longer (negatively) characterized by a lack of behavior, but (positively) by the existence of an incorrect behavior. In our view, this new semantics, with or without explicit errors, provides a better framework for formal and automated reasoning about Esterel programs.
Termination analysis of logic programs through combination of type-based norms
Authors: Bruynooghe Maurice , Codish Michael , Gallagher John P. , Genaim Samir , Vanhoof Wim
Published: June 2007

This article makes two contributions to the work on semantics-based termination analysis for logic programs. The first involves a novel notion of
type
-
based
norm where for a given type, a corresponding norm is defined to count in a term the number of subterms of that type. This provides a collection of candidate norms, one for each type defined in the program. The second enables an analyzer to base termination proofs on the combination of several different norms. This is useful when different norms are better suited to justify the termination of different parts of the program. Application of the two contributions together consists in considering the combination of the type-based candidate norms for a given program. This results in a powerful and practical technique. Both contributions have been introduced into a working termination analyzer. Experimentation indicates that they yield state-of-the-art results in a fully automatic analysis tool, improving with respect to methods that do not use both types and combined norms.
Fast online pointer analysis
Authors: Hirzel Martin , Dincklage Daniel Von , Diwan Amer , Hind Michael
Published: June 2007

Pointer analysis benefits many useful clients, such as compiler optimizations and bug finding tools. Unfortunately, common programming language features such as dynamic loading, reflection, and foreign language interfaces, make pointer analysis difficult. This article describes how to deal with these features by performing pointer analysis online during program execution. For example, dynamic loading may load code that is not available for analysis before the program starts. Only an online analysis can analyze such code, and thus support clients that optimize or find bugs in it. This article identifies all problems in performing Andersen's pointer analysis for the full Java language, presents solutions to these problems, and uses a full implementation of the solutions in a Java virtual machine for validation and performance evaluation. Our analysis is fast: On average over our benchmark suite, if the analysis recomputes points-to results upon each program change, most analysis pauses take under 0.1 seconds, and add up to 64.5 seconds.
Deciding equivalences among conjunctive aggregate queries
Authors: Cohen Sara , Nutt Werner , Sagiv Yehoshua
Published: June 2007

Equivalence of aggregate queries is investigated for the class of conjunctive queries with comparisons and the aggregate operators count, count-distinct, min, max, and sum. Essentially, this class contains unnested SQL queries with the above aggregate operators, with a where clause consisting of a conjunction of comparisons, and without a having clause. The comparisons are either interpreted over a domain with a dense order (like the rationals) or with a discrete order (like the integers). Characterizations of equivalence differ for the two cases. For queries with either max or min, equivalence is characterized in terms of dominance mappings, which can be viewed as a generalization of containment mappings. For queries with the count-distinct operator, a sufficient condition for equivalence is given in terms of equivalence of conjunctive queries under set semantics. For some special cases, it is shown that this condition is also necessary. For conjunctive queries with comparisons but without aggregation, equivalence under bag-set semantics is characterized in terms of isomorphism. This characterization essentially remains the same also for queries with the count operator. Moreover, this characterization also applies to queries with the sum operator if the queries have either constants or comparisons, but not both. In the general case (i.e., both comparisons and constants), the characterization of the equivalence of queries with the sum operator is more elaborate. All the characterizations given in the paper are decidable in polynomial space.
The measurement calculus
Authors: Danos Vincent , Kashefi Elham , Panangaden Prakash
Published: June 2007

Measurement-based quantum computation has emerged from the physics community as a new approach to quantum computation where the notion of measurement is the main driving force of computation. This is in contrast with the more traditional circuit model that is based on unitary operations. Among measurement-based quantum computation methods, the recently introduced one-way quantum computer [Raussendorf and Briegel 2001] stands out as fundamental.

We develop a rigorous mathematical model underlying the one-way quantum computer and present a concrete syntax and operational semantics for programs, which we call
patterns
, and an algebra of these patterns derived from a denotational semantics. More importantly, we present a calculus for reasoning locally and compositionally about these patterns. We present a rewrite theory and prove a general standardization theorem which allows all patterns to be put in a semantically equivalent standard form. Standardization has far-reaching consequences: a new physical architecture based on performing all the entanglement in the beginning, parallelization by exposing the dependency structure of measurements and expressiveness theorems.

Furthermore we formalize several other measurement-based models, for example, Teleportation, Phase and Pauli models and present compositional embeddings of them into and from the one-way model. This allows us to transfer all the theory we develop for the one-way model to these models. This shows that the framework we have developed has a general impact on measurement-based computation and is not just particular to the one-way quantum computer.
Perwez Shahabuddin, 1962--2005
Authors: Andradóttir Sigrún , Glasserman Paul , Glynn Peter W. , Heidelberger Philip , Juneja Sandeep
Published: June 2007

Perwez Shahabuddin was an accomplished researcher, teacher, and participant in the simulation community. This article provides an overview of his career and a summary of some of his many professional accomplishments.
Exploiting regenerative structure to estimate finite time averages via simulation
Authors: Kang Wanmo , Shahabuddin Perwez , Whitt Ward
Published: June 2007

We propose nonstandard simulation estimators of expected time averages over finite intervals [0,
t
], seeking to enhance estimation efficiency. We make three key assumptions: (i) the underlying stochastic process has regenerative structure, (ii) the time average approaches a known limit as time
t
increases and (iii) time 0 is a regeneration time. To exploit those properties, we propose a
residual-cycle estimator
, based on data from the regenerative cycle in progress at time
t
, using only the data
after
time
t
. We prove that the residual-cycle estimator is unbiased and more efficient than the standard estimator for all sufficiently large
t
. Since the relative efficiency increases in
t
, the method is ideally suited to use when applying simulation to study the rate of convergence to the known limit. We also consider two other simulation techniques to be used with the residual-cycle estimator. The first involves
overlapping cycles
, paralleling the technique of overlapping batch means in steady-state estimation; multiple observations are taken from each replication, starting a new observation each time the initial regenerative state is revisited. The other technique is
splitting
, which involves independent replications of the terminal period after time
t
, for each simulation up to time
t
. We demonstrate that these alternative estimators provide efficiency improvement by conducting simulations of queueing models.
Rare events, splitting, and quasi-Monte Carlo
Authors: L'Ecuyer Pierre , Demers Valérie , Tuffin Bruno
Published: June 2007

In the context of rare-event simulation, splitting and importance sampling (IS) are the primary approaches to make important rare events happen more frequently in a simulation and yet recover an unbiased estimator of the target performance measure, with much smaller variance than a straightforward Monte Carlo (MC) estimator. Randomized quasi-Monte Carlo (RQMC) is another class of methods for reducing the noise of simulation estimators, by sampling more evenly than with standard MC. It typically works well for simulations that depend mostly on very few random numbers. In splitting and IS, on the other hand, we often simulate Markov chains whose sample paths are a function of a long sequence of independent random numbers generated during the simulation. In this article, we show that RQMC can be used jointly with splitting and/or IS to construct better estimators than those obtained by either of these methods alone. We do that in a setting where the goal is to estimate the probability of reaching
B
before reaching (or returning to)
A
when starting
A
from a distinguished state not in
B
, where
A
and
B
are two disjoint subsets of the state space, and
B
is very rarely reached. This problem has several practical applications. The article is in fact a two-in-one: the first part provides a guided tour of splitting techniques, introducing along the way some improvements in the implementation of multilevel splitting. At the end of the article, we also give examples of situations where splitting is not effective. For these examples, we compare different ways of applying IS and combining it with RQMC.
Using data mining techniques and rough set theory for language modeling
Authors: Chen Yong , Chan Kwok-Ping
Published: June 2007

In this article, we propose a new postprocessing strategy, word suggestion, based on a multiple word trigger-pair language model for Chinese character recognizers. With the word suggestion strategy, Chinese character recognizers may even achieve a recognition rate greater than the top-n candidate recognition rate. To construct the multiple word trigger-pair model, data mining techniques are used to alleviate the intensive computation problem. Furthermore, rough set theory is first used in the study to discover negatively correlated relationships between words in order to prevent introducing wrong words in the process of word suggestion.
Measuring similarity between transliterations against noise data
Authors: Hsu Chung-Chian , Chen Chien-Hsing , Shih Tien-Teng , Chen Chun-Kai
Published: June 2007

When editors of newspapers and magazines translate proper nouns from foreign languages into Chinese, the Chinese translation (termed transliterations) they choose will typically be phonetically similar to the original word. With many different translators working without a common standard, there may be many different Chinese transliterations for the same proper noun, such as using the same sounds but different Chinese characters or even using different sounds and characters. This causes confusion for the reader and, more importantly, leads to incomplete Chinese Web search results. This article investigates the similarity comparison of transliterations as a first step toward solving the incomplete search problem. We devise a method based on comparing digitalized Chinese character (or Hanzi) sounds. Along with four other methods based on comparing grapheme or phoneme similarity, we compare their performance of identifying synonymous transliterations against noise words taken from Web pages. Experimental results indicate that our method surpasses the other methods due to its advantage of containing more discriminative information in sound vectors. The method performing the second best is based on a scheme which assigns similarity between phonemes by carefully considering articulatory features of phonemes, including using multivalued features and placing different weights on the features. Among six pinyin schemes used to romanize Chinese transliterations, the Tongyong scheme outperforms the others.
An exploration of the principles underlying redundancy-based factoid question answering
Authors: Lin Jimmy
Published: June 2007

The so-called “redundancy-based” approach to question answering represents a successful strategy for mining answers to factoid questions such as “Who shot Abraham Lincoln?” from the World Wide Web. Through contrastive and ablation experiments with Aranea, a system that has performed well in several TREC QA evaluations, this work examines the underlying assumptions and principles behind redundancy-based techniques. Specifically, we develop two theses: that stable characteristics of data redundancy allow factoid systems to rely on external “black box” components, and that despite embodying a data-driven approach, redundancy-based methods encode a substantial amount of knowledge in the form of heuristics. Overall, this work attempts to address the broader question of “what really matters” and to provide guidance for future researchers.
Approaching and leave-taking
Authors: Tang John C.
Published: June 2007

A major difference between face-to-face interaction and computer-mediated communication is how contact negotiation---the way in which people start and end conversations---is managed. Contact negotiation is especially problematic for distributed group members who are separated by distance and thus do not share many of the cues needed to help mediate interaction. An understanding of what resources and cues people use to negotiate making contact when face-to-face identifies ways to design support for contact negotiation in new technology to support remote collaboration. This perspective is used to analyze the design and use experiences with three communication prototypes: Desktop Conferencing Prototype, Montage, and Awarenex. These prototypes use text, video, and graphic indicators to share the cues needed to gracefully start and end conversations. Experiences with using these prototypes focused on how these designs support the interactional commitment of the participants---when they have to commit their attention to an interaction and how flexibly that can be negotiated. Reviewing what we learned from these research experiences identifies directions for future research in supporting contact negotiation in computer-mediated communication.
Prediction of leakage power under process uncertainties
Authors: Chang Hongliang , Sapatnekar Sachin S.
Published: June 2007

In this article, we present a method to analyze the total leakage current of a circuit under process variations, considering interdie and intradie variations as well as the effect of the spatial correlations of intradie variations. The approach considers both the subthreshold and gate tunneling leakage power, as well as their interactions. With process variations, each leakage component is approximated by a lognormal distribution, and the total chip leakage is computed as a sum of the correlated lognormals. Since the lognormals to be summed are large in number and have complicated correlation structures due to both spatial correlations and the correlation among different leakage mechanisms, we propose an efficient method to reduce the number of correlated lognormals for summation to a manageable quantity. We do so by identifying dominant states of leakage currents and taking advantage of the spatial correlation model and input states at the gates. An improved approach utilizing the principal components computed from spatially correlated process parameters is also proposed to further improve runtime efficiency. We show that the proposed methods are effective in predicting the probability distribution of total chip leakage, and that ignoring spatial correlations can underestimate the standard deviation of full-chip leakage power.