bluuebunny/crossref_metadata_2025 huggingface dataset:
Application Study on Bubble Detection in a Metallic Bubble Column Using Electrical Resistance Tomography
Authors: Ridzuan Aw Suzanna , Abdul Rahim Ruzairi , Rahiman Mohd Hafiz Fazalul , Mohd Yunus Fazlul Rahman , Fadzil Naizatul Shima , Zawahir Mohd Zikrillah , Jumaah Mohd Fahjumi , Pusppanathan Muhammad Jaysuman , Nor Ayub Nor Muzakkir , Abdul Wahab Yasmin , Bunyamin Salinda
Published: August 2014

Electrical resistance tomography (ERT) has been chosen as the field of study because of its advantages of being low cost, suitable for various kinds and sizes of pipes and vessels, having no radiation hazard, and being non-intrusive. In the development of ERT systems for metallic bubble column, prior knowledge of the fundamental process of the ERT system whilst improving the design and operation of the process equipment is essential. The fabricated electrodes need to be electrically insulated from the metal wall. Besides that, conducting boundary strategy is implemented to overcome the grounding effect of the metallic vessel.
Electric Potential of Various 4-electrode Segmentation Excitation for Electrical Capacitance Tomography System
Authors: Mohammad Din Shahrulnizahani , Azmi Aizat , Pei Song Chee , Abdul Rahim Ruzairi , Pei Ling Leow
Published: August 2014

Electrical Capacitance Tomography (ECT) system is a non-intrusive method to detect variation of permittivity distribution in a closed pipe. ECT offers fast response, cheap and non-radiation system. However, it suffers from soft-field effect. One of the proposed solutions to overcome this problem is by applying segmentation excitation, which is to have more than one electrode excited at one time. This paper focuses on various segmentation excitations of 4-electrode combinations using COMSOL Multiphysics software. The electrical potential is recorded at the center of the pipe to study the strength of the electrical potential. The result indicates that 4-electrode adjacent configuration recorded 1.005 x 10-9V at the center of the pipe as compared to 0.838 x 10-9V for opposite configuration. This effect shows 16.6% difference in electrical potential at the center of the pipe.
Study and Design of an Ultrasonic Flow Tomographic Front-End Multi Level Measurement System
Authors: Chiew Loon Goh , Abdul Rahim Ruzairi , Ridzuan Aw Suzanna , Mohd Yunus Fazlul Rahman , Nor Ayob Nor Muzakkir , Fazalul Rahiman Mohd Hafiz , Ahmad Anita , Ahmad Nasaruddin , Abbas Khairul Hamimah
Published: August 2014

With the rapid evolution of electro-acoustical technology, ultrasonic tomography has made considerable progress in industry. An ultrasonic tomography system provides non-invasive and non-intrusive flow visualisation that enhances the understanding of fluid flow processes. The function of ultrasonic tomography is to continuously monitor the dynamics of liquid flow without interrupting the flow. The ultrasonic tomography technique is fully supported by a front-end hardware system. The front end is defined as all the hardware circuitries, including the ultrasonic transducer up to the Analogue-to-Digital Convertors (ADCs), even though the primary focus is the analogue signal processing components. We present here the challenges and trade-offs in the implementation of a front-end system by first explaining the basic operation of such a system, and then indicating what particular performance parameters are needed to ensure optimal system operation. Based on the results from our research studies, we propose an improved front-end multi-level solution that is more accurate than previous solutions and provides real-time measurement capability.
Reynolds Number–Strouhal Number Relationship for Cylindrical Bluff Body with Variation of Aspect Ratio in High Reynolds Number
Authors: Che Sidik Nor Azwadi , Wah Yen Tey
Published: August 2014

The effect between Reynolds number and bluff body aspect ratio to the flow parameters such as Strouhal number and drag coefficient are studied. The range of Reynolds number applied is within 10000 and 200000 while three aspect ratio (Ar) where Ar = 1.0, 1.5 and 2.0 are implemented. Finite volume method with the aid of ANSYS CFX codes is deployed using the turbulence SST model. Equations of Re-St relationship for Ar 1.0 and 1.5 are then hypothesized as well in this paper for the range of 10000<Re<100000.
Correlational Analyses Between Mathematics Anxiety and Mathematics Achievement Among Vocational College Students
Authors: Mohd Rameli Mohd Rustam , Kosnin Azlina , Said Hamdan , Tajuddin Norashuha , Abdul Karim Noriadah , Thuy Van Nguyen
Published: August 2014

Students with mathematics anxiety have always been found different from their non-anxious peers on measures of mathematics performance. The current study investigated the phenomenon of mathematics anxiety among vocational college students and its relationship with mathematics achievement. A total of 150 second year students were selected to complete the mathematics anxiety scale. Relative mean analysis indicated that 50% (n=75) of the samples were categorized as mathematics anxiety students. Bivariate correlation analysis revealed that a significant negative correlation exists between mathematics anxiety and mathematics achievement. The results of simple regression showed that mathematics anxiety was a significant predictor of mathematics achievement. Findings of this study suggest that the phenomenon of mathematics anxiety among vocational college students should be addressed in order to ensure that they can perform well in mathematics courses and thus achieve their aims to graduate successfully.
Effects of Aluminosilicate Mineral Nano-Clay Fillers on Polysulfone Mixed Matrix Membrane for Carbon Dioxide Removal
Authors: P.C. Oh , N. A. Mansur
Published: August 2014

Over the last few decades, significant improvements in the performance of polymeric membranes for gas separation have been made.  Nevertheless, the existing membrane materials need to be enhanced in order to fully exploit their gas separation application opportunities on industrial scale. Mixed matrix membrane which combines the advantages of the highly selective fillers and desirable properties of the polymer matrix is explored to overcome the trade-off trend between gas permeability and selectivity.  This paper describes the effect of aluminosilicate mineral nano-clay fillers on polysulfone (PSF) mixed matrix membrane. In this study, different types of montmorillonite (MMT) nano-clays were used as fillers to fabricate asymmetric flat sheet mixed matrix membrane (MMM) via dry-wet phase inversion method. The interaction between the type of organoclay and its loading is also studied. The synthesis of MMM required N-methyl-2-pyrrolidone (NMP) as solvent and deionized water as coagulant. The fabricated MMMs were characterized by thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and field emission scanning electron microsropy (FESEM). Thin asymmetric membrane with dense skin layer and porous sub-structure was successfully fabricated. Results showed enhancement in MMM stability relative to neat PSF membrane. It is also found that higher nano-clay loading resulted in significant agglomeration, nevertheless, there appears to be improved adhesion between the polymer and nano-clay.
Asymmetric Polysulfone-Cloisite 15A® Nanocomposite Membrane for Gas Separation
Authors: Zulhairun A. K. , Ismail A. F. , Mustafaa A.
Published: August 2014

Defect-free asymmetric Polysulfone (PSF)-Cloisite 15A® nanocomposite membrane was fabricated with the intention to investigate the gas permeation behavior of the resulting material combination. Various weights of Cloisite 15A® organoclay were added into PSF matrices by solution intercalation method assisted by sonication dispersion. The gas permeation properties of the PSF-Cloisite 15A® nanocomposite membranes were evaluated by pure gases: nitrogen, methane, and carbon dioxide. The distribution of Cloisite 15A® particles in PSF matrices was analyzed by SEM. The gas flux of the PSF-Cloisite 15A® nanocomposite membranes declined as the Cloisite 15A® weight loading increased. The CO2/CH4 and CO2/N2 pure gas selectivity of PSF nanocomposite with 0.5 wt. % of Cloisite 15A® loading exceeded that of neat PSF membrane. The decrease in flux followed by the increase in pure gas selectivity was related to the way in which the clay layers were dispersed in the PSF matrices. Considerable improvement in CO2 selectivity was attainable even by incorporating low amount of such layered structure nanoparticle which can be attractive in producing robust materials for CO2-removal membranes from CO2-containing gas streams such as post-combustion and natural gas streams.
Synthesis and Preparation of Asymmetric PSf/ZIF-8 Mixed Matrix Membrane for CO2/CH4 Separation
Authors: Md Nordin Nik Abdul Hadi , Ismail Ahmad Fauzi , Mustafa Azeman
Published: August 2014

Utilizing nano-size filler into polymer matrix would overcome challenges in developing MMM  by providing good dispersion in polymer matrix, high contact polymer-filler even at low filler loading. Asymmetric neat Polysulfone (PSf) and PSf/Zeolitic Imidazole Framework-8 (PSf/ZIF-8) mixed matrix membrane was prepared using dry/wet inversion method. Membrane prepared was coated with 3wt% of polydimethylsiloxane (PDMS) in n-hexane and undergoes heat treatment. The membranes was characterized using x-ray diffraction (XRD), thermagravimetric analysis (TGA), differential scanning calorimetry (DSC), and gas permeation test at 4 bar. XRD pattern revealed that ZIF-8 was successfully synthesis with crystal size around 73nm. Lowered membrane Tg after embodiment of ZIF-8 suggests that additional free volume form, while thermal stability up to 350°C related to ZIF-8 stability. Neat PSf prepared shows CO2 permeance at 4.97 GPU with CO2/CH4 selectivity at 7.52. Interestingly, incorporation of ZIF-8 showing improvement for both CO2 permeance and CO2/CH4 selectivity up to 51% and 47% respectively. Thus, employing nano ZIF-8 as filler into PSf matrix has resultant promising membrane for CO2/CH4 separation.
Characterization of Polyethersulfone/Cloisite 15A Mixed Matrix Membrane for CO2/CH4 Separation
Authors: Ismail N. M. , Ismail A. F. , Mustaffa A.
Published: August 2014

Asymmetric hybrid organic-inorganic clay mineral polyethersulfone (PES) flat sheet membranes were prepared from solution containing Cloisite15A® (C15A) in the mixture of solvent and polymer. Neat PES and MMM were prepared through dry/wet phase inversion method. The newly developed membranes were characterized by means of SEM. The effect of filler addition, evaporation time and coating protocol towards the performance of the membrane was investigated. The measurement was carried out at room temperature and the upstream pressure was 3 bar while the downstream pressure was atmospheric. Experimental results showed that selectivity for MMM fabricated with 0.25 wt% clay loading at evaporation time of 40 s is lower compared to those prepared at higher evaporation time. After coating with silicone rubber solution and heat treated, the resultant membranes exhibited selectivity enhancement of CO2/CH4 from 7.9 to 28.4 for pristine PES, while PES/C15A1 and PES/C15A2 showed a selectivity improvement of 2.29 to 18.72 and 10.24 to 33.49 each. Optimum evaporation time and appropriate coating and heat treatment have significant contribution in developing high performance MMM for gas CO2/CH4 separation.
Refined abelian Stark conjectures and the equivariant leading term conjecture of Burns
Authors: Sano T.
Published: August 2014

We formulate a conjecture which generalizes Darmon’s ‘refined class number formula’. We discuss relations between our conjecture and the equivariant leading term conjecture of Burns. As an application, we give another proof of the ‘except$2$-part’ of Darmon’s conjecture, which was first proved by Mazur and Rubin.
Trihyperkähler reduction and instanton bundles on
Authors: Jardim Marcos , Verbitsky Misha
Published: August 2014

A trisymplectic structure on a complex $2n$-manifold is a three-dimensional space ${\rm\Omega}$ of closed holomorphic forms such that any element of ${\rm\Omega}$ has constant rank $2n$, $n$ or zero, and degenerate forms in ${\rm\Omega}$ belong to a non-degenerate quadric hypersurface. We show that a trisymplectic manifold is equipped with a holomorphic 3-web and the Chern connection of this 3-web is holomorphic, torsion-free, and preserves the three symplectic forms. We construct a trisymplectic structure on the moduli of regular rational curves in the twistor space of a hyperkähler manifold, and define a trisymplectic reduction of a trisymplectic manifold, which is a complexified form of a hyperkähler reduction. We prove that the trisymplectic reduction in the space of regular rational curves on the twistor space of a hyperkähler manifold $M$ is compatible with the hyperkähler reduction on $M$. As an application of these geometric ideas, we consider the ADHM construction of instantons and show that the moduli space of rank $r$, charge $c$ framed instanton bundles on $\mathbb{C}\mathbb{P}^{3}$ is a smooth trisymplectic manifold of complex dimension $4rc$. In particular, it follows that the moduli space of rank two, charge $c$ instanton bundles on $\mathbb{C}\mathbb{P}^{3}$ is a smooth complex manifold dimension $8c-3$, thus settling part of a 30-year-old conjecture.
A Numerical Model for Ammonia/Water Absorption From a Bubble Expanding at a Submerged Nozzle Into a Binary Nanofluid
Authors: Su Fengmin , Ma Hongbin , Deng Yangbo , Zhao Nannan
Published: August 2014

An absorber is a major component in the absorption refrigeration systems, and its performance remarkably affects the overall system performance. A mathematical model for ammonia absorption from a bubble expanding at a submerged nozzle into a binary nanofluid was developed to analyze the effects of binary nanofluid on ammonia absorption in the forming process of a bubble. The combined effects of nanoparticles on heat transfer, mass transfer, and bubble size all were considered in the model. The concentration of nanoparticles, the radius of the nozzle, and the flow rate of ammonia vapor were considered as the key parameters. The numerical results showed that the enhancement of binary nanofluid for bubble absorption has the analogous tendency with the mass transfer enhancement of binary nanofluid. The diameter of the nozzle and the flow rate of ammonia vapor hardly affect the enhancement of the binary nanofluid for the absorption of bubble growing stage. The current investigation can result in a better understanding of the absorption process occurring in thermally driven absorption refrigeration systems.
Predicting Boundary Friction of Aging Limited Slip Differentials
Authors: Berglund K. , Marklund P. , Larsson R. , Olsson R.
Published: August 2014

The prediction of friction is a challenge for scientists and engineers in a wide variety of applications in industry today. One such an application is the limited slip differential. The friction characteristics of the wet clutch are central to the performance of the limited slip differential system. Frictional changes with aging of the limited slip differential affect both the torque transfer accuracy and the tendencies to vibrations and noise generation due to stick-slip or shudder. Therefore, the objective of this work is to establish a method to predict the frictional changes of aging limited slip differential systems. In this study, a number of experiments were performed to establish a method to predict the changes in boundary friction with time due to aging. Accelerated aging was performed for different sets of operating conditions. Results from the tests were used to establish and verify a model to predict friction increase in limited slip differentials. The method assumes that frictional changes with aging are caused by decreased concentrations of friction modifying additives. The decrease in concentration was assumed to depend on the lubricant bulk temperature according to the Arrhenius equation. The model agreed well with tests performed at operating conditions close to the real operating conditions of the limited slip differential. The developed method can be implemented in a vehicle where it can be used to compensate for frictional changes and to indicate when service should be made.
Failure Mechanics—Part II: The Central and Decisive Role of Graphene in Defining the Elastic and Failure Properties for all Isotropic Materials
Authors: Christensen Richard M.
Published: August 2014

Continuing from Part I (Christensen, 2014, “Failure Mechanics—Part I: The Coordination Between Elasticity Theory and Failure Theory for all Isotropic Materials,” ASME J. Appl. Mech., 81(8), p. 081001), the relationship between elastic energy and failure specification is further developed. Part I established the coordination of failure theory with elasticity theory, but subject to one overriding assumption: that the values of the involved Poisson's ratios always be non-negative. The present work derives the physical proof that, contrary to fairly common belief, Poisson's ratio must always be non-negative. It can never be negative for homogeneous and isotropic materials. This is accomplished by first probing the reduced two-dimensional (2D) elasticity problem appropriate to graphene, then generalizing to three-dimensional (3D) conditions. The nanomechanics analysis of graphene provides the key to the entire development. Other aspects of failure theory are also examined and concluded positively. Failure theory as unified with elasticity theory is thus completed, finalized, and fundamentally validated.
Model for Elastohydrodynamic Lubrication of Multilayered Materials
Authors: Wang Zhanjiang , Yu Chenjiao , Wang Qian
Published: August 2014

A novel model is constructed for solving elastohydrodynamic lubrication (EHL) of multilayered materials. Because the film thickness equation needs the term of the deformation caused by pressure, the key problem for the EHL of elastic multilayered materials is to develop a method for calculating their surface deformations, or displacements, caused by pressure. The elastic displacements and stresses can be calculated by employing the discrete-convolution and fast Fourier transform (DC-FFT) method with influence coefficients. For the contact of layered materials, the frequency response functions (FRFs), relating pressure to surface displacements and stress components, derived from the Papkovich–Neuber potentials are applied. The influence coefficients can be obtained by employing FRFs. The EHL of functionally graded material (FGM) can also be well solved using a multilayer material system. The effects of material layers and property gradient on EHL film thickness and pressure are further investigated.
Biomechanics of the Canine Mandible During Bone Transport Distraction Osteogenesis
Authors: Zapata Uriel , Dechow Paul C. , Watanabe Ikuya , Elsalanty Mohammed E. , Opperman Lynne A.
Published: August 2014

This study compared biomechanical patterns between finite element models (FEMs) and a fresh dog mandible tested under molar and incisal physiological loads in order to clarify the effect of the bone transport distraction osteogenesis (BTDO) surgical process. Three FEMs of dog mandibles were built in order to evaluate the effects of BTDO. The first model evaluated the mandibular response under two physiological loads resembling bite processes. In the second model, a 5.0 cm bone defect was bridged with a bone transport reconstruction plate (BTRP). In the third model, new regenerated bony tissue was incorporated within the defect to mimic the surgical process without the presence of the device. Complementarily, a mandible of a male American foxhound dog was mechanically tested in the laboratory both in the presence and absence of a BTRP, and mechanical responses were measured by attaching rosettes to the bone surface of the mandible to validate the FEM predictions. The relationship between real and predicted values indicates that the stress patterns calculated using FEM are a valid predictor of the biomechanics of the BTDO procedures. The present study provides an interesting correlation between the stiffness of the device and the biomechanical response of the mandible affected for bone transport.
Characteristic Equation-Based Dynamic Analysis of a Three-Revolute Prismatic Spherical Parallel Kinematic Machine
Authors: Zhang Jun , Dai Jian S. , Huang Tian
Published: August 2014

A three-revolute prismatic spherical (3-RPS) parallel kinematic machine (PKM) module is proposed as an alternative solution for high-speed machining (HSM) tool. Considering the PKM as a typical compliant parallel device, whose three limb assemblages have bending, extending, and torsional deflections, this paper applies screw theory to establish an analytical compliance model for the device. The developed compliance model is then combined with the energy method to deduce a comprehensive dynamic model of the 3-RPS module. The solution for the characteristic equations of the dynamic model leads to the modal properties of the PKM module. Based on the eigenvalue decomposition of the characteristic equations, a modal analysis is conducted. The natural frequencies and corresponding mode shapes at typical and nontypical configurations are analyzed and compared with finite element analysis (FEA) results. With an algorithm of workspace partitions combining with eigenvalue decompositions, the distributions of natural frequencies throughout the workspace are predicted to reveal a strong dependency of dynamic characteristics on mechanism's configurations. At the last stage, the effects of some design parameters on system dynamic characteristics are investigated with the purpose of providing useful information for the conceptual design and performance improvement for the PKM.
The Use of the Adjoint Method for Solving Typical Optimization Problems in Multibody Dynamics
Authors: Nachbagauer Karin , Oberpeilsteiner Stefan , Sherif Karim , Steiner Wolfgang
Published: August 2014

The present paper illustrates the potential of the adjoint method for a wide range of optimization problems in multibody dynamics such as inverse dynamics and parameter identification. Although the equations and matrices included show a complicated structure, the additional effort when combining the standard forward solver to the adjoint backward solver is kept in limits. Therefore, the adjoint method shows an efficient way to incorporate inverse dynamics to engineering multibody applications, e.g., trajectory tracking or parameter identification in the field of robotics. The present paper studies examples for both, parameter identification and optimal control, and shows the potential of the adjoint method in solving classical optimization problems in multibody dynamics.
Biomechanical Effect of Altered Lumbar Lordosis on Intervertebral Lumbar Joints During the Golf Swing: A Simulation Study
Authors: Bae Tae Soo , Cho Woong , Kim Kwon Hee , Chae Soo Won
Published: August 2014

Although the lumbar spine region is the most common site of injury in golfers, little research has been done on intervertebral loads in relation to the anatomical–morphological differences in the region. This study aimed to examine the biomechanical effects of anatomical–morphological differences in the lumbar lordosis on the lumbar spinal joints during a golf swing. The golf swing motions of ten professional golfers were analyzed. Using a subject-specific 3D musculoskeletal system model, inverse dynamic analyses were performed to compare the intervertebral load, the load on the lumbar spine, and the load in each swing phase. In the intervertebral load, the value was the highest at the L5–S1 and gradually decreased toward the T12. In each lumbar spine model, the load value was the greatest on the kypholordosis (KPL) followed by normal lordosis (NRL), hypolordosis (HPL), and excessive lordosis (EXL) before the impact phase. However, results after the follow-through (FT) phase were shown in reverse order. Finally, the load in each swing phase was greatest during the FT phase in all the lumbar spine models. The findings can be utilized in the training and rehabilitation of golfers to help reduce the risk of injury by considering individual anatomical–morphological characteristics.
Probing the Instability of a Cluster of Slip Bonds Upon Cyclic Loads With a Coupled Finite Element Analysis and Monte Carlo Method
Authors: Chen Xiaofeng , Chen Bin
Published: August 2014

Cells are subjected to cyclic loads under physiological conditions, which regulate cellular structures and functions. Recently, it was demonstrated that cells on substrates reoriented nearly perpendicular to the stretch direction in response to uni-axial cyclic stretches. Though various theories were proposed to explain this observation, the underlying mechanism, especially at the molecular level, is still elusive. To provide insights into this intriguing observation, we employ a coupled finite element analysis (FEA) and Monte Carlo method to investigate the stability of a cluster of slip bonds upon cyclic loads. Our simulation results indicate that the cluster can become unstable upon cyclic loads and there exist two characteristic failure modes: gradual sliding with a relatively long lifetime versus catastrophic failure with a relatively short lifetime. We also find that the lifetime of the bond cluster, in many cases, decreases with increasing stretch amplitude and also decreases with increasing cyclic frequency, which appears to saturate at high cyclic frequencies. These results are consistent with the experimental reports. This work suggests the possible role of slip bonds in cellular reorientation upon cyclic stretch.
Online Eccentricity Monitoring of Seamless Tubes in Cross-Roll Piercing Mill
Authors: Guo Weihong , Chen Rui , Jin Jionghua (Judy)
Published: August 2014

Wall-thickness eccentricity is a major dimensional deviation problem in seamless steel tube production. Although eccentricity is mainly caused by abnormal process conditions in the cross-roll piercing mill, most seamless tube plants lack the monitoring at the hot piercing stage but only inspect the quality of finished tubes using ultrasonic testing (UT) at the end of all manufacturing processes. This paper develops an online monitoring technique to detect abnormal conditions in the cross-roll piercing mill. Based on an image-sensing technique, process operation condition can be extracted from the vibration signals. Optimal frequency features that are sensitive to tube wall-thickness variation are then selected through the formulation and solution of a set-covering optimization problem. Hotelling T2 control charts are constructed using the selected features for online monitoring. The developed monitoring technique enables early detection of eccentricity problems at the hot piercing stage, which can facilitate timely adjustment and defect prevention. The monitoring technique developed in this paper is generic and can be widely applied to the hot piercing process of various products. This paper also provides a general framework for effectively analyzing image-based sensing data and establishing the linkage between product quality information and process information.
Loss and dysfunction of Vδ2
+
γδ T cells are associated with clinical tolerance to malaria
Authors: Jagannathan Prasanna , Kim Charlie C. , Greenhouse Bryan , Nankya Felistas , Bowen Katherine , Eccles-James Ijeoma , Muhindo Mary K. , Arinaitwe Emmanuel , Tappero Jordan W. , Kamya Moses R. , Dorsey Grant , Feeney Margaret E.
Published: August 2014

Loss and dysfunction of γδ T cells is associated with tolerance to
P. falciparum
infection.
Abundant and Diverse Clustered Regularly Interspaced Short Palindromic Repeat Spacers in Clostridium difficile Strains and Prophages Target Multiple Phage Types within This Pathogen
Authors: Hargreaves Katherine R. , Flores Cesar O. , Lawley Trevor D. , Clokie Martha R. J.
Published: August 2014

Clostridium difficile
is an important human-pathogenic bacterium causing antibiotic-associated nosocomial infections worldwide. Mobile genetic elements and bacteriophages have helped shape
C. difficile
genome evolution. In many bacteria, phage infection may be controlled by a form of bacterial immunity called the clustered regularly interspaced short palindromic repeats/CRISPR-associated (CRISPR/Cas) system. This uses acquired short nucleotide sequences (spacers) to target homologous sequences (protospacers) in phage genomes.
C. difficile
carries multiple CRISPR arrays, and in this paper we examine the relationships between the host- and phage-carried elements of the system. We detected multiple matches between spacers and regions in 31
C. difficile
phage and prophage genomes. A subset of the spacers was located in prophage-carried CRISPR arrays. The CRISPR spacer profiles generated suggest that related phages would have similar host ranges. Furthermore, we show that
C. difficile
strains of the same ribotype could either have similar or divergent CRISPR contents. Both synonymous and nonsynonymous mutations in the protospacer sequences were identified, as well as differences in the protospacer adjacent motif (PAM), which could explain how phages escape this system. This paper illustrates how the distribution and diversity of CRISPR spacers in
C. difficile
, and its prophages, could modulate phage predation for this pathogen and impact upon its evolution and pathogenicity.

IMPORTANCE
Clostridium difficile
is a significant bacterial human pathogen which undergoes continual genome evolution, resulting in the emergence of new virulent strains. Phages are major facilitators of genome evolution in other bacterial species, and we use sequence analysis-based approaches in order to examine whether the CRISPR/Cas system could control these interactions across divergent
C. difficile
strains. The presence of spacer sequences in prophages that are homologous to phage genomes raises an extra level of complexity in this predator-prey microbial system. Our results demonstrate that the impact of phage infection in this system is widespread and that the CRISPR/Cas system is likely to be an important aspect of the evolutionary dynamics in
C. difficile
.
Structured approach in improving weekend handovers in a medical high dependency unit
Authors: Patel Roma , Thiagarajan Prarthana
Published: August 2014

Weekend admissions to hospital have been associated with adverse patient outcomes, including higher morbidity and mortality risk in general medicine and surgery. The reasons behind this are likely to be multifactorial and include reduced senior clinician-led care, decreased overall workforce, and ineffective or incomplete handover. With the advent of shift-work patterns, robust handover between medical teams is of paramount importance, particularly before weekends. This has been reflected in recent publications by Royal College of Physicians (acute care toolkit 1: handover, May 2011), that identified handover as an error-prone process and issued guidelines designed to optimise its effectiveness.

The aim of this project was to evaluate weekend patient mortality and success of handover on the medical high dependency unit of a large teaching hospital in the United Kingdom, before and after introduction of a structured handover tool on Friday afternoons during May 2013. This unit is registrar-led at weekends. Weekend mortality decreased from 43% in March 2013 to 22% in May 2013 (odds ratio 0.37, 95% CI 0.19-0.68, p=0.07). Documentation of resuscitation status and escalation plans increased from 75% in March 2013 to 93% in May 2013. There was universal positive feedback from registrars involved with the handover tool, who provided senior cover during the weekends in May 2013. It is hoped that structured, written handover will ultimately become commonplace in this unit and will improve patient safety at weekends.
Controlling parameter for unsaturated soil property functions: validated on the unsaturated shear strength
Authors: Schnellmann Reto , Rahardjo Harianto , Schneider Hans R.
Published: August 2014

Prediction equations for unsaturated soil property functions have become more attractive because laboratory tests of unsaturated soils are time consuming and expensive. To ensure that predicted soil property functions represent soil behaviour reasonably well, appropriate selection of the parameter that controls the performance of these prediction equations becomes imperative. Deduced from the typical desaturation characteristics of a soil, the effective degree of saturation has emerged to be the controlling parameter for unsaturated soil property functions. In this paper, soil suction is considered to become ineffective in affecting unsaturated soil property functions at and beyond the residual state. Comparisons between experimental shear strength data and predicted values obtained using the concept proposed in this study show a good agreement.
Estimating reach-specific fish movement probabilities in rivers with a Bayesian state-space model: application to sea lamprey passage and capture at dams
Authors: Holbrook Christopher M. , Johnson Nicholas S. , Steibel Juan P. , Twohey Michael B. , Binder Thomas R. , Krueger Charles C. , Jones Michael L.
Published: August 2014

Improved methods are needed to evaluate barriers and traps for control and assessment of invasive sea lamprey (Petromyzon marinus) in the Great Lakes. A Bayesian state-space model provided reach-specific probabilities of movement, including trap capture and dam passage, for 148 acoustic tagged invasive sea lamprey in the lower Cheboygan River, Michigan, a tributary to Lake Huron. Reach-specific movement probabilities were combined to obtain estimates of spatial distribution and abundance needed to evaluate a barrier and trap complex for sea lamprey control and assessment. Of an estimated 21 828 – 29 300 adult sea lampreys in the river, 0%–2%, or 0–514 untagged lampreys, could have passed upstream of the dam, and 46%–61% were caught in the trap. Although no tagged lampreys passed above the dam (0/148), our sample size was not sufficient to consider the lock and dam a complete barrier to sea lamprey. Results also showed that existing traps are in good locations because 83%–96% of the population was vulnerable to existing traps. However, only 52%–69% of lampreys vulnerable to traps were caught, suggesting that traps can be improved. The approach used in this study was a novel use of Bayesian state-space models that may have broader applications, including evaluation of barriers for other invasive species (e.g., Asian carp (Hypophthalmichthys spp.)) and fish passage structures for other diadromous fishes.
Habitat connectivity, complexity, and quality: predicting adult coho salmon occupancy and abundance
Authors: Anlauf-Dunn Kara J. , Ward Eric J. , Strickland Matt , Jones Kim
Published: August 2014

The distribution, quality, and connectivity of instream habitat can influence adult salmon occupancy and abundance patterns and alter population dynamics. In this study, we evaluated the relationships between adult coho salmon (Oncorhynchus kisutch) occupancy and abundance with instream habitat conditions, including measures of spawning gravel, habitat complexity, and juvenile rearing habitat. We used corresponding adult salmon spawning and instream habitat data collected within coastal Oregon watersheds as part of a long-term monitoring program. We modeled two processes as a function of habitat characteristics: the number of coho salmon when they were present and the occupancy probabilities of coho salmon. The results from both submodels were then combined into an estimate of total abundance at each site. Adult coho salmon occupancy was best predicted by the capacity of the habitat to support parr during the winter, complex pools, percent bedrock, and site distance to the ocean. Although lacking the predictive capacity of the occupancy model, increases in adult coho counts at sites were also influenced by the site distance to the ocean, and there is evidence that both percent gravel and complex pools may also be valuable predictors. By taking advantage of long-term datasets with broad spatial range, using an integrative approach across coho salmon life stages, and utilizing innovative Bayesian modeling techniques, this study is a unique approach to understanding a complicated ecological narrative. Combined, our results indicate the spatial distribution and proximity of spawning and rearing habitats may maximize productivity for coho salmon in coastal Oregon watersheds.
Best practices for use of stable isotope mixing models in food-web studies
Authors: Phillips Donald L. , Inger Richard , Bearhop Stuart , Jackson Andrew L. , Moore Jonathan W. , Parnell Andrew C. , Semmens Brice X. , Ward Eric J.
Published: August 2014

Stable isotope mixing models are increasingly used to quantify consumer diets, but may be misused and misinterpreted. We address major challenges to their effective application. Mixing models have increased rapidly in sophistication. Current models estimate probability distributions of source contributions, have user-friendly interfaces, and incorporate complexities such as variability in isotope signatures, discrimination factors, hierarchical variance structure, covariates, and concentration dependence. For proper implementation of mixing models, we offer the following suggestions. First, mixing models can only be as good as the study and data. Studies should have clear questions, be informed by knowledge of the system, and have strong sampling designs to effectively characterize isotope variability of consumers and resources on proper spatio-temporal scales. Second, studies should use models appropriate for the question and recognize their assumptions and limitations. Decisions about source grouping or incorporation of concentration dependence can influence results. Third, studies should be careful about interpretation of model outputs. Mixing models generally estimate proportions of assimilated resources with substantial uncertainty distributions. Last, common sense, such as graphing data before analyzing, is essential to maximize usefulness of these tools. We hope these suggestions for effective implementation of stable isotope mixing models will aid continued development and application of this field.
Production of scalar particles in electric field on de Sitter expanding universe
Authors: Băloi Mihaela-Andreea
Published: August 2014

The scalar particle production from vacuum in the presence of an electric field, on the de Sitter spacetime is studied. We use perturbation methods to define the transition amplitude. We obtain that the momentum is not conserved in this process. The probability density of pair production is computed by squaring the transition amplitude. Our graphical representations show that, the probability of scalar particle production was important only in the early stages of the universe, when Hubble's constant was very large in comparison with the mass of the particle. Also, we propose here a criterion for particle–antiparticle separation.
Semantic Question Answering Using Wikipedia Categories Clustering
Authors: Stratogiannis Georgios , Siolas Georgios , Stafylopatis Andreas
Published: August 2014

We describe a system that performs semantic Question Answering based on the combination of classic Information Retrieval methods with semantic ones. First, we use a search engine to gather web pages and then apply a noun phrase extractor to extract all the candidate answer entities from them. Candidate entities are ranked using a linear combination of two IR measures to pick the most relevant ones. For each one of the top ranked candidate entities we find the corresponding Wikipedia page. We then propose a novel way to exploit Semantic Information contained in the structure of Wikipedia. A vector is built for every entity from Wikipedia category names by splitting and lemmatizing the words that form them. These vectors maintain Semantic Information in the sense that we are given the ability to measure semantic closeness between the entities. Based on this, we apply an intelligent clustering method to the candidate entities and show that candidate entities in the biggest cluster are the most semantically related to the ideal answers to the query. Results on the topics of the TREC 2009 Related Entity Finding task dataset show promising performance.
A Transparent and Decentralized Model of Perception and Action for Intelligent Virtual Agents
Authors: Anastassakis George , Panayiotopoulos Themis
Published: August 2014

Intelligent virtual agent behaviour is a crucial element of any virtual environment application as it essentially brings the environment to life, introduces believability and realism and enables complex interactions and evolution over time. However, the development of mechanisms for virtual agent perception and action is neither a trivial nor a straight-forward task. In this paper we present a model of perception and action for intelligent virtual agents that meets specific requirements and can as such be systematically implemented, can seamlessly and transparently integrate with knowledge representation and intelligent reasoning mechanisms, is highly independent of virtual world implementation specifics, and enables virtual agent portability and reuse.
Satisfaction Degree Based Interactive Decision Making under Hesitant Fuzzy Environment with Incomplete Weights
Authors: Liao Huchang , Xu Zeshui
Published: August 2014

Multi-criteria decision making with hesitant fuzzy information is a new research topic since the hesitant fuzzy set was firstly proposed. This paper investigates a multi-criteria decision making problem where the weight information is partially known. We firstly propose the hesitant fuzzy positive ideal solution and the hesitant fuzzy negative ideal solution. Motivated by the TOPSIS (Technique for Order Preference by Similarity to an ideal Solution) method, we definite the satisfaction degree of an alternative, based on which several optimization models are derived to determinate the weights. Subsequently, in order to make a more reasonable decision, we introduce an interactive method based on some optimization models for multi-criteria decision making problems with hesitant fuzzy information. Finally, a practical example on evaluating the service quality of airlines is provided to illustrate our models and method.
PEOPLE WATCH
Authors: Lim Rachel
Published: August 2014

Drugs in the Real World
Energy Harvesting in a Nonlinear Cantilever Piezoelastic Beam System Excited by Random Vertical Vibrations
Authors: Borowiec Marek , Litak Grzegorz , Friswell Michael I. , Adhikari Sondipon
Published: August 2014

The vertical elastic beam with vertical ambient excitation is proposed as an energy harvester. The beam has a tip mass and piezoelectric patches which transduce the bending strains induced by the stochastic force caused by vertical kinematic forcing into electrical charge. We focus on the region with a fairly large amplitude of voltage output where the beam overcomes the potential barrier. Increasing the noise level allows the transition from single well oscillations to inter-well stochastic jumps with more power generation.
China's “Ghost Cities”
Authors: YU Hong
Published: August 2014

Some Chinese cities are now notoriously known as “ghost cities” for their empty skyscrapers, luxury apartments and magnificent squares. These “ghost cities” are a result of excessive housing and infrastructure construction, and speculation on property demand. The emergence of ghost cities is a consequence of China's land-centred urbanisation. Land-centred urbanisation is rooted in local GDPism, which in turn results in aggressive developmentalism and excessive investment among China's local governments.
Targeting steroid receptor coactivator 1 with antisense oligonucleotides increases insulin-stimulated skeletal muscle glucose uptake in chow-fed and high-fat-fed male rats
Authors: Cantley Jennifer L. , Vatner Daniel F. , Galbo Thomas , Madiraju Anila , Petersen Max , Perry Rachel J. , Kumashiro Naoki , Guebre-Egziabher Fitsum , Gattu Arijeet K. , Stacy Mitchel R. , Dione Donald P. , Sinusas Albert J. , Ragolia Louis , Hall Christopher E. , Manchem Vara Prasad , Bhanot Sanjay , Bogan Jonathan S. , Samuel Varman T.
Published: August 2014

The steroid receptor coactivator 1 (SRC1) regulates key metabolic pathways, including glucose homeostasis. SRC1−/− mice have decreased hepatic expression of gluconeogenic enzymes and a reduction in the rate of endogenous glucose production (EGP). We sought to determine whether decreasing hepatic and adipose SRC1 expression in normal adult rats would alter glucose homeostasis and insulin action. Regular chow-fed and high-fat-fed male Sprage-Dawley rats were treated with an antisense oligonucleotide (ASO) against SRC1 or a control ASO for 4 wk, followed by metabolic assessments. SRC1 ASO did not alter basal EGP or expression of gluconeogenic enzymes. Instead, SRC1 ASO increased insulin-stimulated whole body glucose disposal by ∼30%, which was attributable largely to an increase in insulin-stimulated muscle glucose uptake. This was associated with an approximately sevenfold increase in adipose expression of lipocalin-type prostaglandin D2 synthase, a previously reported regulator of insulin sensitivity, and an approximately 70% increase in plasma PGD2 concentration. Muscle insulin signaling, AMPK activation, and tissue perfusion were unchanged. Although GLUT4 content was unchanged, SRC1 ASO increased the cleavage of tether-containing UBX domain for GLUT4, a regulator of GLUT4 translocation. These studies point to a novel role of adipose SRC1 as a regulator of insulin-stimulated muscle glucose uptake.
Dynamic gene expression patterns in animal models of early and late heart failure reveal biphasic-bidirectional transcriptional activation of signaling pathways
Authors: Rowell Janelle , Koitabashi Norimichi , Kass David A. , Barth Andreas S.
Published: August 2014

Altered cardiac gene expression in heart failure (HF) has mostly been identified by single-point analysis of end-stage disease. This may miss earlier changes in gene expression that are transient and/or directionally opposite to those observed later. Myocardial datasets from the largest microarray data repository (Gene Expression Omnibus) yielded six HF studies with time-course data. Differentially expressed transcripts between nonfailing controls, early HF (<3 days after cardiac insult) and late HF (usually >2 wk) were determined, and analysis of KEGG pathways and predicted regulatory control elements performed. We found that gene expression followed varying patterns: Downregulation of metabolic pathways occurred early and was sustained into late-stage HF. In contrast, most signaling pathways undergo a complex biphasic pattern: Calcium signaling, p53, apoptosis, and MAPK pathways displayed a bidirectional response, declining early but rising late. These profiles were compatible with specific microRNA (miRNA) and transcription regulators: Estrogen-related receptor-α and myocyte-enhancer factor-2 binding sites were overrepresented in the promoter regions of downregulated transcripts. Concurrently, there were overrepresented binding sites for E2f and ETS family members (E-Twenty Six, including Gabp, Elf1, and Ets2), serum response and interferon regulated factor in biphasic-bidirectional and late-upregulated transcripts. Binding sites for miRNAs downregulated by HF were more common in upregulated transcripts (e.g., miRNA-22,-133a/b, and -150 in early HF and miRNA-1,-9,-499 in late HF). During the development of HF, gene expression is characterized by dynamic overlapping sets of transcripts controlled by specific interrelated regulatory mechanisms. While metabolic gene classes show early and sustained downregulation in HF, signaling pathways undergo a complex biphasic pattern with early down- and more pronounced late upregulation.