bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of gastrostomy in head and neck cancer: a systematic review to identify areas for future research
Authors: Paleri V. , Patterson J.
Published: April 2010

Clin. Otolaryngol. 2010, 35, 177–189

Objectives:  To perform a systematic review of studies, which investigate the role of gastrostomy tube feeding in head and neck squamous cell cancer.

Design:  A systematic review of the English literature, identifying areas of clinical equipoise and recommendations for future studies.

Main outcome measures:  Varying practices in G‐tube use in HNSCC, the benefits and disadvantages of G‐tubes, the effect of G‐tube placement on multidimensional outcomes in patients with head and neck cancer, including quality of life and health economics and to draw themes that may lend themselves to future research.

Results:  The search identified 216 articles of which 59 were considered relevant. During treatment, a significant number of patients need enteral nutritional supplementation through nasogastric or G‐tubes. Gastrostomy tubes have a good safety profile. Most clinicians agree that the use should be restricted to advanced tumours. Studies on prophylactic insertion of G‐tubes do not show a consistent advantage to the nutritional status compared with NG tubes. At 1 year, G‐tube retention rates vary between 10% and 30%. The presence of a feeding tube has a negative impact on quality of life. Placing G‐tubes may have an adverse effect on swallowing after chemoradiation.

Conclusions:  There is a lack of consensus among clinicians about indications for placing G‐tubes. There is sufficient equipoise in this area for further investigation of the effect of varying feeding practices on functional outcomes, quality of life and health economics.
Mediators and moderators in early intervention research
Authors: Breitborde Nicholas J. K. , Srihari Vinod H. , Pollard Jessica M. , Addington Donald N. , Woods Scott W.
Published: April 2010

Aim: The goal of this paper is to provide clarification with regard to the nature of mediator and moderator variables and the statistical methods used to test for the existence of these variables. Particular attention will be devoted to discussing the ways in which the identification of mediator and moderator variables may help to advance the field of early intervention in psychiatry.

Methods: We completed a literature review of the methodological strategies used to test for mediator and moderator variables.

Results: Although several tests for mediator variables are currently available, recent evaluations suggest that tests which directly evaluate the indirect effect are superior. With regard to moderator variables, two approaches (‘pick‐a‐point’ and regions of significance) are available, and we provide guidelines with regard to how researchers can determine which approach may be most appropriate to use for their specific study. Finally, we discuss how to evaluate the clinical importance of mediator and moderator relationships as well as the methodology to calculate statistical power for tests of mediation and moderation.

Conclusion: Further exploration of mediator and moderator variables may provide valuable information with regard to interventions provided early in the course of a psychiatric illness.
Synchronization and portfolio performance of threatened salmon
Authors: Moore Jonathan W. , McClure Michelle , Rogers Lauren A. , Schindler Daniel E.
Published: April 2010

Interpopulation variation in dynamics can buffer species against environmental change. We compared population synchrony in a group of threatened Chinook salmon in the highly impacted Snake River basin (Oregon, Washington, Idaho) to that in the sockeye salmon stock complex of less impact Bristol Bay (Alaska). Over the last 40 years, >90% of populations in the Snake River basin became more synchronized with one another. However, over that period, sockeye populations from Alaska did not exhibit systemic changes in synchrony. Coincident with increasing Snake River population synchrony, there was an increase in hatchery propagation and the number of large dams, potentially homogenizing habitats and populations. A simulation using economic portfolio theory revealed that synchronization of Snake River salmon decreased risk‐adjusted portfolio performance (the ratio of portfolio productivity to variance) and decreased benefits of population richness. Improving portfolio performance for exploited species, especially given future environmental change, requires protecting a diverse range of populations and the varied habitats upon which they depend.
Individualised Assessment of Response to Clopidogrel in Patients Presenting with Acute Coronary Syndromes: A Role for Short Thrombelastography?
Authors: Cotton J.M. , Worrall A.M. , Hobson A.R. , Smallwood A. , Amoah V. , Dunmore S. , Nevill A.M. , Rajendra R. , Vickers J. , Curzen N.
Published: April 2010

Introduction: There is considerable interindividual variation in response to the antiplatelet agent clopidogrel. Hyporesponse predicts negative outcomes in patients presenting with a variety of ischemic cardiac conditions and following intracoronary stent placement. Many tests of clopidogrel activity are time consuming and complex. Short thromboelastography (s‐TEG) allows rapid measurement of platelet clopidogrel response. Aims: We initiated this study to investigate the utility of s‐TEG in assessing the response to clopidogrel in patients presenting with acute coronary syndromes (ACS) and to compare these results with established clopidogrel monitoring techniques. Methods: Patients admitted with unstable angina (UA) or Non ST elevation myocardial infarction (NSTEMI) undergoing coronary angiography were recruited. After routine loading with clopidogrel, all patients were tested with s‐TEG and Accumetrics Verify‐Now rapid platelet function analyzer (VN‐RPFA). We used the modified TEG technique of measuring area under the curve at 15 min (AUC15), which allows a rapid estimation of antiplatelet response. Vasodilator‐stimulated phosphoprotein phosphorylation (VASP) was also tested in a subgroup of patients. Clinical follow‐up was obtained at 1 year. s‐TEG results were correlated with VN‐RPFA and VASP findings. Results: A total of 49 patients (33 male, mean age 63) were recruited and tested with s‐TEG and VN‐RPFA and a total of 39 patients were also assessed with VASP. s‐TEG readings correlated well with VN‐RPFA (r2= 0.54, P < 0.0001) and VASP (r2= 0.26, P= 0.001). Conclusion: s‐TEG provides timely results which compare to current tests of clopidogrel activity. This technique can also be used to measure a variety of other clotting parameters and as such could develop into a valuable near patient test for the interventional cardiologist.
The Teacher's Discourse Moves: A Framework for Analyzing Discourse in Mathematics Classrooms
Authors: Krussel Libby , Edwards Barbara , Springer G.T.
Published: April 2010

In this paper a framework is proposed for analyzing the deliberate actions taken by a teacher to participate in or influence the discourse in mathematics classrooms, and such actions are referred to as the teacher's discourse moves. This work synthesizes elements of several other discourse frameworks, including those of Richards, Sfard, Cobb, and Knuth and Peressini. Expanding on the improvisational dance metaphor of Heaton's, the framework views the teacher in the additional multiple roles as a Choreographer/Stage Manager/Director of classroom discourse. Several research applications of the discourse framework to collegiate mathematics education are discussed, including discourse around collaborative problem solving in Treisman Emerging Scholars workshops, a video‐based study of a college‐level geometry course for teachers, discourse in wireless networked classrooms, and the asynchronous discourse in an online statistics course.
Preparing K‐8 Preservice Teachers in a Content Course for Standards‐Based Mathematics Pedagogy
Authors: Lubinski Cheryl A. , Otto Albert D.
Published: April 2010

Many K–8 preservice teachers have not experienced learning mathematics in a standards‐based classroom. This article describes a mathematics content course designed to provide preservice teachers experiences in learning mathematics that will help build a solid foundation for a standards‐based methods course. The content course focuses on developing preservice teachers' mathematical knowledge, as well as helping them realize what it means to learn mathematics that is taught using the pedagogy in the Principles and Standards for School Mathematics (National Council of Teachers of Mathematics, 2000). Furthermore, findings are presented from a study on this course that describe students' pre‐ and postcourse beliefs, attitudes, and perceptions of what it means to learn and teach mathematics. These findings provide evidence that the students in the study are beginning to understand what is meant by a standards‐based classroom. Data were collected from surveys and interviews. Quotes from the students who aspire to be elementary teachers are used throughout the article to support the points.
Pre‐service Teachers' Beliefs about Knowledge, Mathematics, and Science
Authors: Cady Jo Ann , Rearden Kristin
Published: April 2010

This study examines the beliefs of K‐8 preservice teachers during a content methods course. The goals of this course included exposing the preservice teachers to student‐centered instructional methods for math and science and encouraging the development of lessons that would integrate mathematics and science. Prior research suggested that one must consider preservice teachers' epistemic beliefs (Cady, Meier, & Lubinski, 2006a) as it influences their interpretation of the teacher education program. In this study, preservice teachers' epistemic beliefs were identified, their beliefs about mathematics and science teaching and learning were identified and compared, and their descriptions of lessons that integrated mathematics and science were assessed. Findings suggest that preservice teachers made decisions based on an external locus of control and harbored greater anxiety about teaching math as compared to teaching science. They also indicate that the integration of mathematics and science in lesson plans was contrived.
Understanding a Teacher's Reflections: A Case Study of a Middle School Mathematics Teacher
Authors: Kwon Na‐Young , Orrill Chandra Hawley
Published: April 2010

The purpose of this research was to understand how one teacher reflected on different classroom situations and to understand whether the teacher's approach to these reflections changed over time. For the purposes of this study, we considered reflection as the teacher's act of interpreting her own practices and students' thinking to make sense of student understanding and how teaching might relate to that understanding. We investigated a middle school mathematics teacher's reflection on her students while watching videotapes of her classroom and categorized the reflection as Assess, Interpret, Describe, Justify, and Extend. The results show a higher percentage of Extend instances in later interviews than in earlier ones indicating the teacher's increasing attention to her own teaching in how her students developed their understanding. In addition, her reflection became clearer and better integrated as defined by the Cohen and Ball's triangle of interactions.
The Frequency, Variation, and Function of Graphical Representations within Standardized State Science Tests
Authors: Yeh Yi‐Fen Y. , McTigue Erin M.
Published: April 2010

The purpose of this study was to determine the extent that diagrammatic literacy is necessary for success on standardized science tests at the late‐elementary and middle grade levels. Towards this goal, we quantified the frequency, form and function of graphical representations on select state science tests. 985 tests items from 14 states were analyzed with 52.7% of the test items including graphical representations. The majority of these graphics, 79.5%, contained information that was essential for correctly answering the questions. The paper also discussed the trends of graphical representations in grade levels and alignment to national standards, following with teacher‐implications.
The Relationship Between Lesson Study and Self‐Efficacy
Authors: Sibbald Tim
Published: April 2010

This article addresses a gap in the literature by developing a theory that bridges lesson study and self‐efficacy. Since self‐efficacy has been linked to student achievement, the theory is important as an explanatory mechanism linking lesson study to student achievement. The theory was developed using grounded theory based on primary source data primarily from planning and debriefing meetings. The theory demonstrates that lesson study is linked to self efficacy through a content continuum which implies that issues from pedagogical content knowledge to deeper conceptual matters can be addressed. It also implies that constraints arising in lesson study are most frequently limitations of pedagogical content knowledge which can be mitigated by a community of practice that provides appropriate resources and subject expertise.
Science Teacher Efficacy and Outcome Expectancy as Predictors of Students' End‐of‐Instruction (EOI) Biology I Test Scores
Authors: Angle Julie , Moseley Christine
Published: April 2010

The purpose of this study was to compare teacher efficacy beliefs of secondary Biology I teachers whose students' mean scores on the statewide End‐of‐Instruction (EOI) Biology I test met or exceeded the state academic proficiency level (Proficient Group) to teacher efficacy beliefs of secondary Biology I teachers whose students' mean scores on the EOI Biology I test fell below the state academic proficiency level (Non‐proficient Group). The mean difference on the Personal Science Teaching Efficacy (PSTE) subscale scores between the two groups was not statistically significant. This indicates that personal science teaching efficacy was not statistically related to how a teacher s students scored on the EOI Biology I test.

The mean difference on the Science Teaching Outcome Expectancy (STOE) subscale scores demonstrated a statistically significant difference between the science teaching outcome expectancy of the Non‐proficient Group and Proficient Group teachers. Proficient Group teachers had significantly higher STOE scores than teachers Non‐proficient Group teachers. This finding suggests that End‐of‐Instruction Biology I test scores were related to the expectations that a teacher held for his/her students to learn biology regardless of student home environment, availability of classroom materials, or student motivation.
Unbiased survival estimates and evidence for skipped breeding opportunities in females
Authors: Muths Erin , Scherer Rick D. , Lambert Brad A.
Published: April 2010

1. Estimates of demographic parameters for females, in many organisms, are sparse. This is particularly worrisome as more and more species are faced with high extinction probabilities and conservation increasingly depends on actions dictated by complex predictive models that require accurate estimates of demographic parameters for each sex and species.

2. This study assesses demographic parameters, specifically temporary emigration and survival, for females, a class that has been difficult to investigate historically because of lack of data. Amphibians provide a particularly good example because there is global concern about amphibian decline; yet most demographic parameter estimates are based on data from males, which we show can lead to erroneous conclusions.

3. We use 10 years of capture–recapture data from boreal toads (Bufo boreas) and the multi‐state open robust design model to provide evidence for the occurrence of skipped breeding opportunities (i.e. temporary emigration) in females. This is the first time that the open robust design model has been applied to an analysis of an amphibian population that we are aware of.

4. We determined that the transition from breeder to non‐breeder is obligate and the probability of a non‐breeder remaining a non‐breeder is 64%; thus, temporary emigration is first‐order Markovian in nature, where breeding probability is dependent on the previous year’s activity, i.e. if a female did not breed in year one, there is a 36% chance that she will breed in year two. With temporary emigration accounted for, we estimated between‐year female survival at 87%.

5. Establishing the occurrence of temporary emigration not only reduces bias in estimates of survival probabilities but also provides information about expected breeding attempts by females, a critical element in understanding the ecology of an organism and the impacts of outside stressors and conservation actions.
Use of antiviral medications against equine herpes virus associated disorders
Authors: Wong D. M. , Maxwell L. K. , Wilkins P. A.
Published: April 2010

Numerous types of equine herpesviruses (EHV) continue to afflict horses resulting in a variety of clinical manifestations. While many of the clinical manifestations of EHV are self‐limiting or require only supportive care, some clinical expressions of EHV infections cause severe risk to the horse's overall health and can result in abortion, long‐term deficits or death. Antiviral medications are infrequently utilised therapeutics in equine medicine and their exact efficacy is largely unknown. However, the use of antiviral medications may potentially decrease convalescent time and improve outcome in horses with EHV‐related diseases. Thus, equine practitioners should consider the potential use of antiviral medications in the future. The purpose of this article is to familiarise the equine practitioner with current information in regard to antiviral medications and their potential uses in equine medicine.
The Propagation of Star-Shaped Brittle Cracks
Authors: Rassoulova Nazile B.
Published: April 2010

The paper studies the dynamical propagation of star-shaped cracks symmetrically arranged in an elastic thin plate, subjected to the action of instantly applied, comprehensively (uniformly) stretching stresses, which implies a self-similar problem with homogeneous stresses and velocities of particles. Occurrence of such motion patterns is established through experiments. By using the Smirnov–Sobolev functional-invariant solutions method and a careful choice of mappings, the problem is reduced to some boundary value problem of the theory of complex variable functions, and exact analytic solution of the original problem, including a closed-form solution for important stress intensity coefficient near the end of the crack, is derived. We also establish a fundamental theoretical limit imposed on the number of cracks—there has to be at least three cracks.
Three-Dimensional Vibration Analysis of Toroidal Sectors With Solid Circular Cross-Sections
Authors: Zhou D. , Cheung Y. K. , Lo S. H.
Published: April 2010

This paper studies the free vibration of circular toroidal sectors with circular cross-sections based on the three-dimensional small-strain, linear elasticity theory. A set of orthogonal coordinates, composing the polar coordinate (r,θ) with the origin on the cross-sectional centerline of the sector and the circumferential coordinate φ with the origin at the curvature center of the centerline, is developed to describe the displacements, strains, and stresses in the sector. Each of the displacement components is taken as a product of four functions: a set of Chebyshev polynomials in φ and r coordinates, a set of trigonometric series in θ coordinate, and a boundary function in terms of φ. Frequency parameters and mode shapes have been obtained via a displacement-based extremum energy principle. The upper bound convergence of the first eight frequency parameters accurate up to five figures has been achieved. The present results agree with those from the finite element solutions. The effect of the ratio of curvature radius R to the cross-sectional radius a and the subtended angle φ0 on the frequency parameters of the sectors are discussed in detail. The three-dimensional vibration mode shapes are also plotted.
Prediction of Formation of Wavy Surfaces in Rolled Plates by Post-Buckling Analysis
Authors: Kim Jinseok , Pattnaik Shrikant , Kim Jay
Published: April 2010

Excessive wavy surfaces formed by a cold- or hot-rolling process in a thin plate degrades the value of the plate significantly, which is called the flatness problem in the industry. It is a result of post-buckling due to the residual stress caused by the rolling process. Because the buckling occurs in a very long, continuous plate, a unique difficulty of the problem as a buckling problem is that the buckling length is not given but has to be found. In many previous works, the length that gives the lowest critical load of the plate for the given load profile was taken as the buckling length. In this work, it is shown that this approach is flawed, and a new approach is developed to solve the flatness problem by extending a classic post-buckling analysis method based on the energy principle. The approach determines the buckling length and amplitude without using any unfounded assumptions or hypothesis. Using simple displacement functions, approximate solutions are obtained in closed forms for the plate subjected to a linearly distributed residual stress. The new solution approach can be used to determine the condition for the maximum rolling production that does not cause the flatness problem.
A Reduced Second-Order Approach for Linear Viscoelastic Oscillators
Authors: Adhikari Sondipon
Published: April 2010

This paper proposes a new approach for the reduction in the model-order of linear multiple-degree-of-freedom viscoelastic systems via equivalent second-order systems. The assumed viscoelastic forces depend on the past history of motion via convolution integrals over kernel functions. Current methods to solve this type of problem normally use the state-space approach involving additional internal variables. Such approaches often increase the order of the eigenvalue problem to be solved and can become computationally expensive for large systems. Here, an approximate reduced second-order approach is proposed for this type of problems. The proposed approximation utilizes the idea of generalized proportional damping and expressions of approximate eigenvalues of the system. A closed-form expression of the equivalent second-order system has been derived. The new expression is obtained by elementary operations involving the mass, stiffness, and the kernel function matrix only. This enables one to approximately calculate the dynamical response of complex viscoelastic systems using the standard tools for conventional second-order systems. Representative numerical examples are given to verify the accuracy of the derived expressions.
An Alternative Derivation of the Quaternion Equations of Motion for Rigid-Body Rotational Dynamics
Authors: Udwadia Firdaus E. , Schutte Aaron D.
Published: April 2010

This note provides a direct method for obtaining Lagrange’s equations describing the rotational motion of a rigid body in terms of quaternions by using the so-called fundamental equation of constrained motion.
Effect of Velocity-Slip Boundary Conditions on Jeffery–Hamel Flow Solutions
Authors: Al-Nimr M. A. , Hammoudeh Vladimir A. , Hamdan M. A.
Published: April 2010

In the present work, the Jeffery–Hamel flow problem has been studied using both first- and second-order velocity-slip models, and then compared with the no-slip model. The objectives are to observe the behavior of the flow predicted by the two slip models and to establish criteria for using the two velocity-slip models. The study concentrates on examining the effect of the change in the Knudsen number (Kn) on the velocity profiles, magnitude of slip at the wall, and skin friction coefficient. Assuming that a difference between the two slip models of the order of 10% or less justifies the use of the simple first-order model, the transitional Kn numbers have been found. These Kn numbers depend on the flow direction, being either inflow or outflow. Also, there are three distinct regions that specify where to use each of the no-slip, first-order, and second-order slip models. Further, the reversal of the flow has been investigated as a function of the Kn number and for different Re⋅α, where Re is Reynolds number and α is the wall angle. Using the second-order slip models, it is found that as the Kn number increases, reversal occurs at Re⋅α smaller than the 10.31 value at which flow reversal happens in the no-slip model, and increasing the Kn number leads to a reduction in the skin friction coefficient in all cases except when reversal occurs.
Buckling of Stressed and Pressurized Thin Films on Substrates
Authors: Dion Éloi , Grilhé Jean , Colin Jérôme , Coupeau Christophe
Published: April 2010

The buckling solutions for a stressed thin film deposited on a semi-infinite rigid substrate have been determined in the framework of the Föppl–von Karman’s theory of thin plates and the perturbed bifurcation theory when pressures are applied onto the lower and upper free surfaces of the buckled film. It is found that the equilibrium solutions of the film are modified compared with the classical case of the Euler column, as well as the critical stress above which the film buckles.
Phase-Field Modeling of Domain Structure Energetics and Evolution in Ferroelectric Thin Films
Authors: Kontsos Antonios , Landis Chad M.
Published: April 2010

A computational model developed based on the phase-field approach is used to model domain structures in ferroelectric thin films and to quantify the effects of strain and applied electric field on the microstructural evolution, and on the induced dielectric, electrostrictive, and piezoelectric film properties. Theoretically predicted vortex-like polydomain and experimentally observed bidomain and monodomain film morphologies are modeled using the continuum phase-field approach. A nonlinear finite element method is used to solve the boundary value problems relevant to ferroelectric thin films. The computed results agree with the Kittel law for specific ranges of film strain. Simulations that track the domain structure evolution and compute ferroelectric thin film properties given the film dimensions and the imposed electromechanical boundary conditions are also reported.
Enhanced Ductility in Sheet Metals Produced by Cladding a Ductile Layer
Authors: Chen X. X. , Wu P. D. , Lloyd D. J. , Embury J. D. , Huang Y.
Published: April 2010

The effect of cladding a ductile layer on necking and fracture in sheet metals under plane strain tension is studied numerically using the finite element method based on the Gurson damage model. It is demonstrated that the cladding increases both the necking and fracture strains. The increase in necking strain is due to the fact that cladding a ductile layer enhances the overall work hardening for the layered metal sheets according to the rule of mixtures. Furthermore, the increase in necking strain slows down the development of the triaxial tensile stress inside the neck, which delays the void nucleation and growth, and which, in turn, contributes to enhancement in ductility.
Thermomechanical Analysis of Film-on-Substrate System With Temperature-Dependent Properties
Authors: Huang YongAn , Yin ZhouPing , Xiong YouLun
Published: April 2010

Thermomechanical analysis of global and local buckling is presented to show temperature effects on the stress/strain and shape of a film-on-substrate system. First, the strain is expressed as a function of three key temperatures (room, working, and deposit temperatures). Through sensitivity analysis on temperature, polydimethylsiloxane (PDMS) selection is determined to theoretically design film-on-substrate systems with the minimum variation in stress caused by temperatures. Then, the wrinkling behaviors are studied to establish the relationships of critical strain, wavelength, and amplitude with temperature. In addition, the critical working temperature is determined for local buckling. The approximate semi-analytical solution and the finite element simulation are compared by the use of a two-dimensional case of film on a half-space substrate.
N

-Phase Elliptical Inhomogeneities With Internal Uniform Stresses in Plane Elasticity
Authors: Wang Xu
Published: April 2010

We investigate the problem of an N-phase elliptical inhomogeneity in plane elasticity. The elliptical inhomogeneity is bonded to the unbounded matrix through the intermediate (N−2) interphases, and the matrix is subjected to remote uniform stresses. We observe that the stress field inside the elliptical inhomogeneity is still uniform when the following two conditions are satisfied: (i) The formed interfaces are (N−1) confocal ellipses, and (ii) the interphases and the matrix possess the same shear modulus but different Poisson’s ratios. In Appendixes A xB, we also discuss an arbitrary number of interacting arbitrary shaped inhomogeneities embedded in an infinite matrix, and an N-phase inhomogeneity with (N−1) interfaces of arbitrary shape. Here all the phases comprising the composite possess the same shear modulus but different Poisson’s ratios. The results in the main body and in Appendixes A xB are further extended in Appendix C to finite plane strain deformations of compressible hyperelastic harmonic materials.
Method to obtain nonuniformity information from field emission behavior
Authors: Dall’Agnol Fernando F. , de Paulo Alexandre C. , Paredez Pablo , den Engelsen Daniel , Santos Thebano E. A. , Mammana Victor P.
Published: April 2010

This article describes the characterization of field emission from a planar cathode to a spherical anode with the approach curve method (ACM). In such a diode configuration the electric field strength at the cathode surface is nonuniform. This nonuniformity gives an extra degree of freedom and it allows the interpretation of the current-voltage and voltage-distance (V×d) curves in terms of nonuniformity. The authors apply the ACM to Cu emitters to explain the nonlinearity of the V×d curve in ACM measurements. This analysis provides a good insight into field emission phenomena, supporting a method for nonuniformity characterization based on field emission behavior.
Effect of energetic ions on plasma damage of porous SiCOH low-k materials
Authors: Kunnen E. , Baklanov M. R. , Franquet A. , Shamiryan D. , Rakhimova T. V. , Urbanowicz A. M. , Struyf H. , Boullart W.
Published: April 2010

Plasma damage of SiCOH low-k films in an oxygen plasma is studied using a transformer coupled plasma reactor. The concentration of oxygen atoms and O2+ ions is varied by using three different conditions: (1) bottom power only, (2) bottom and top power, and (3) top power only. After plasma exposure, the low-k samples are characterized by various experimental techniques. It is shown that the ion bombardment induced by the bottom power minimizes the plasma damage by increasing the recombination coefficient of oxygen radicals. Contrary to the expectations, the densification of the top surface by ion radiation was limited. The increase in the recombination coefficient is mainly provided by modification of the pore wall surface and creation of chemically active sites stimulating the recombination of oxygen atoms. The results show that a reduction in plasma damage can be achieved without sealing of low-k top surface.
Effects of AlxGa1−xN interlayer for GaN epilayer grown on Si substrate by metal-organic chemical-vapor deposition
Authors: Lin Kung-Liang , Chang Edward-Yi , Hsiao Yu-Lin , Huang Wei-Ching , Luong Tien-Tung , Wong Yuen-Yee , Li Tingkai , Tweet Doug , Chiang Chen-Hao
Published: April 2010

GaN film grown on Si substrate using multilayer AlN/AlxGa1−xN buffer is studied by the low-pressure metal-organic chemical-vapor deposition method. The AlxGa1−xN films with Al composition varying from 1 to 0.66 were used to accommodate the stress induced between GaN and the Si substrate during GaN growth. The correlation of the Al composition in the AlxGa1−xN films with respect to the stress induced in the GaN film grown was studied using high-resolution x-ray diffraction, including symmetrical and asymmetrical ω/2θ scans and reciprocal space maps. It is found that with proper design of the Al composition in the AlxGa1−xN buffer layer, crack-free GaN film can be successfully grown on 6 in. Si (111) substrates using multilayer AlN and AlxGa1−xN buffer layers.
Ultra-thin Titanium Oxide Films on Mo(112), Measured by XPS
Authors: Kumar Dheeraj , Chen Ming Shu , Goodman David W.
Published: April 2010

Two preparation methods were employed to grow a well-ordered ultra-thin titanium oxide film on Mo(112). The first method consisted of growing the films by direct deposition of Ti by chemical vapor deposition, followed by oxidation. Better film quality was obtained by the second method which involved deposition of Ti onto monolayer SiO2/Mo(112), as described in our prior work. By using x-ray photoelectron spectroscopy, Ti was determined to be in +3 oxidation state.
TiO2 Thin Films by Chemical Vapor Deposition: An XPS Characterization
Authors: Barreca Davide , Gasparotto Alberto , Maccato Chiara , Maragno Cinzia , Tondello Eugenio
Published: April 2010

As a part of a comprehensive research work on ZnO-TiO2 nanosystems synthesized by Chemical Vapor Deposition (CVD), we initially devoted our attention to the preparation and characterization of nanocrystalline TiO2 thin films. Specifically, the coatings were obtained by CVD on Si(100) substrates starting from Ti(OiPr)2(dpm)2 (OiPr=iso-propoxy; dpm=2,2,6,6-tetramethyl-3,5-heptanedionate), under a dry O2 atmosphere. The obtained samples were characterized by complementary techniques, namely Glancing Incidence X-ray Diffraction (GIXRD), X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM), for a thorough investigation of their microstructure, chemical composition and morphology. The present contribution is devoted to the XPS analysis of a TiO2 thin film obtained at 450 °C. Besides the wide scan spectrum, detailed spectra for the Ti 2p, O ls and C 1s regions and related data are presented and discussed.
ZnO Nanoplatelets Obtained by Chemical Vapor Deposition, Studied by XPS
Authors: Barreca Davide , Gasparotto Alberto , Maccato Chiara , Maragno Cinzia , Tondello Eugenio
Published: April 2010

Zinc oxide nanoplatelets have been successfully grown on Si(l00) by a catalyst-free Chemical Vapor Deposition (CVD) route starting from a second-generation Zn(II) molecular precursor, Zn(hfa)2?TMEDA (Hhfa=1,1,1,5,5,5-hexafluoro-2,4-pentanedione; TMEDA=N,N,N′,N′-tetramethylethylenediamine). The syntheses were performed under a nitrogen+wet oxygen atmosphere and the best results were obtained at deposition temperatures of 350 and 400 °C. The obtained samples were thoroughly characterized by several techniques, namely Glancing-Incidence X-ray Diffraction (GIXRD), Atomic Force Microscopy (AFM), Field Emission-Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-ray Spectroscopy (EDXS), X-ray Photoelectron (XPS) and X-ray Excited Auger Electron (XE-AES) Spectroscopies. Finally, the photocatalytic performances of ZnO nanoplatelets in the decomposition of the azo-dye Orange II were also evaluated. The present contribution is specifically dedicated to the XPS and XE-AES characterization of a representative ZnO nanoplatelet sample deposited at 350 °C. Beside the wide scan spectrum, detailed spectra for the Zn 2p3/2, Zn 3p, Zn LMM, O 1s, and C 1s are also presented. The obtained results evidenced the formation of pure zinc oxide systems under the adopted synthetic conditions.
Hafnium oxide thin film grown by ALD: An XPS study
Authors: Barreca Davide , Milanov Andrian , Fischer Roland A. , Devi Anjana , Tondello Eugenio
Published: April 2010

Hafnium(IV) oxide thin films were synthesized by atomic layer deposition (ALD) on Si(100) substrates, using an innovative guanidinate-stabilized hafnium amide precursor, [Hf(NEtMe)2(EtMeNC(NiPr)2)2]. In the present work, our attention is focused on a detailed XPS characterization of a representative HfO2 coating grown at 350 °C. Beside the wide scan spectrum, detailed spectra for the O 1s, Hf 4f, Hf 4d and C 1s regions and related data are presented and discussed. The obtained results point out to the formation of HfO2 coatings characterized by the presence of -OH groups, whose main origin is attributed to the use of water as oxidizing agent during the preparation process.
Gd2O3 Nanostructured Thin Films Analyzed by XPS
Authors: Barreca Davide , Gasparotto Alberto , Milanov Andrian , Tondello Eugenio , Devi Anjana , Fischer Roland A.
Published: April 2010

The present work was devoted to the X-ray photoelectron spectroscopy (XPS) investigation of the principal core levels of a nanostructured Gd2O3 thin film. The sample was synthesized by metal organic chemical vapor deposition (MOCVD) from Gd((iPrN)2CNMe2)3 as precursor at 500 °C in an N2/O2 atmosphere. XPS results evidenced a marked Gd2O3 reactivity towards atmospheric CO2 and H2O, leading to a surface composition characterized by the co-presence of gadolinium carbonates/bicarbonates and hydroxides.
CLASSIFICATION OF ACTIONS OF DISCRETE AMENABLE GROUPS ON AMENABLE SUBFACTORS OF TYPE II
Authors: POPA SORIN
Published: April 2010

We prove a classification result for properly outer actions σ of discrete amenable groups G on strongly amenable subfactors of type II, N ⊂ M, a class of subfactors that were shown to be completely classified by their standard invariant [Formula: see text], in [27]. The result shows that the action σ is completely classified in terms of the action it induces on [Formula: see text]. As an application of this, we obtain that inclusions of type IIIλfactors, 0 < λ < 1, having discrete decomposition and strongly amenable graph, are completely classified by their standard invariant.
AN ARCHITECTURE TO SUPPORT PERSONALIZED INTERACTION ACROSS MULTIPLE DIGITALLY AUGMENTED SPACES
Authors: STOICA ADRIAN , AVOURIS NIKOLAOS
Published: April 2010

Any physical space can be augmented with digital information, associated to various locations or artefacts contained in it. In this paper, an abstract architecture is presented, supporting interaction with mobile context aware applications in public digitally augmented spaces. We focus on how this architecture supports personalization of interaction and adaptation. The main goal of the architecture is to allow users to benefit of a uniform and personalized experience across different contexts and spaces. Among the concerns are: to support high interoperability and flexibility and to address issues of privacy and user control. The framework has been tested in typical augmented spaces: a library and a museum. The paper concludes with a set of examples of use of the defined framework that cover typical situations for intra-space and across spaces usage.
SPEECH ENHANCEMENT FOR ROBUST SPEECH RECOGNITION IN MOTORCYCLE ENVIRONMENT
Authors: MPORAS IOSIF , GANCHEV TODOR , KOCSIS OTILIA , FAKOTAKIS NIKOS
Published: April 2010

In the present work, we investigate the performance of a number of traditional and recent speech enhancement algorithms in the adverse non-stationary conditions, which are distinctive for motorcycles on the move. The performance of these algorithms is ranked in terms of the improvement they contribute to the speech recognition accuracy, when compared to the baseline performance, i.e. without speech enhancement. The experiments on the MoveOn motorcycle speech and noise database indicated that there is no equivalence between the ranking of algorithms based on the human perception of speech quality and the speech recognition performance. The Multi-band spectral subtraction method was observed to lead to the highest speech recognition performance.
BEHAVIOUR RECOGNITION FROM VIDEO CONTENT: A LOGIC PROGRAMMING APPROACH
Authors: ARTIKIS ALEXANDER , SKARLATIDIS ANASTASIOS , PALIOURAS GEORGIOS
Published: April 2010

We present a system for recognising human behaviour given a symbolic representation of surveillance videos. The input of our system is a set of time-stamped short-term behaviours, that is, behaviours taking place in a short period of time — walking, running, standing still, etc — detected on video frames. The output of our system is a set of recognised long-term behaviours — fighting, meeting, leaving an object, collapsing, walking, etc — which are pre-defined temporal combinations of short-term behaviours. The definition of a long-term behaviour, including the temporal constraints on the short-term behaviours that, if satisfied, lead to the recognition of the long-term behaviour, is expressed in the Event Calculus. We present experimental results concerning videos with several humans and objects, temporally overlapping and repetitive behaviours. Moreover, we present how machine learning techniques may be employed in order to automatically develop long-term behaviour definitions.
COSMOLOGY FROM ANISOTROPIC DGP BRANEWORLD
Authors: ANSARI RIZWAN UL HAQ , SURESH P. K.
Published: April 2010

We considered an anisotropic brane embedded in a five-dimensional bulk space–time. The Einstein equations and Friedmann equations are obtained. The corresponding Friedmann equations are modified with quadratic corrections to energy density. The anisotropic DGP model also admits a self-accelerating phase in the late universe. The acceleration conditions are obtained and they are consistent with the braneworld scenario. The acceleration condition for DGP model, in the late universe, is dependent on the crossover scale rc.
TOPOLOGICAL BLACK HOLES OF EINSTEIN–YANG–MILLS DILATON GRAVITY
Authors: DEHGHANI M. H. , BAZRAFSHAN A.
Published: April 2010

We present the topological solutions of Einstein dilaton gravity in the presence of a non-Abelian Yang–Mills field. In four dimensions, we consider the So(3) and So(2, 1) semisimple group as the Yang–Mills gauge group, and introduce the black hole solutions with spherical and hyperbolic horizons, respectively. The solution in the absence of dilaton potential is asymptotically flat and exists only with a spherical horizon. Contrary to the nonextreme Reissner–Nordstrom black hole, which has two horizons with a timelike and avoidable singularity, here the solution may present a black hole with a null and unavoidable singularity with only one horizon. In the presence of dilaton potential, the asymptotic behavior of the solutions is neither flat nor anti–de Sitter. These solutions contain a null and avoidable singularity, and may present a black hole with two horizons, an extreme black hole or a naked singularity. We also calculate the mass of the solutions through the use of a modified version of the Brown–York formalism, and consider the first law of thermodynamics.
CONSTRAINING THE RUNAWAY DILATON AND QUINTESSENTIAL DARK ENERGY
Authors: NEUPANE ISHWAREE P. , TROWLAND HOLLY
Published: April 2010

Dark energy is some of the weirdest and most mysterious stuff in the universe that tends to increase the rate of expansion of the universe. Two commonly known forms of dark energy are the cosmological constant, a constant energy density filling space homogeneously, and scalar fields such as quintessence or moduli whose energy density can vary with time. We explore one particular model for dynamic dark energy: quintessence driven by a scalar dilaton field. We propose an ansatz for the form of the dilaton field, |ϕ(a)|mP ≡ α1 ln t + α2tn = α ln a + βa2ζ, where a is the scale factor and α and ζ are parameters of the model. This phenomenological ansatz for ϕ can be motivated by generic solutions of a scalar dilaton field in many effective string theory and string-inspired gravity models in four dimensions. Most of the earlier discussions in the literature correspond to the choice that ζ = 0 so that ϕ(t) ∝ ln t or ϕ(t) ∝ ln a(t). Using a compilation of current data including type Ia supernovae, we impose observational constraints on the slope parameters like α and ζ and then discuss the relation of our results to analytical constraints on various cosmological parameters, including the dark energy equation of state. Some useful constraints are imposed on model parameters like α and ζ as well as on the dark energy/dark matter couplings using results from structure formation. The constraints of this model are shown to encompass the cosmological constant limit within 1σ error bars.
INCLUSION SYSTEMS AND AMALGAMATED PRODUCTS OF PRODUCT SYSTEMS
Authors: BHAT B. V. RAJARAMA , MUKHERJEE MITHUN
Published: April 2010

Here we generalize the concept of Skeide product, introduced by Skeide, of two product systems via a pair of normalized units. This new notion is called amalgamated product of product systems, and now the amalgamation can be done using contractive morphisms. Index of amalgamation product (when done through units) adds up for normalized units but for non-normalized units, the index is one more than the sum. We define inclusion systems and use it as a tool for index computations. It is expected that this notion will have other uses.
LOG-HARNACK INEQUALITY FOR STOCHASTIC DIFFERENTIAL EQUATIONS IN HILBERT SPACES AND ITS CONSEQUENCES
Authors: RÖCKNER MICHAEL , WANG FENG-YU
Published: April 2010

A logarithmic type Harnack inequality is established for the semigroup of solutions to a stochastic differential equation in Hilbert spaces with non-additive noise. As applications, the strong Feller property as well as the entropy-cost inequality for the semigroup are derived with respect to the corresponding distance (cost function).
STOCHASTIC PROPERTIES OF DEGENERATED QUANTUM SYSTEMS
Authors: SAKBAEV VSEVOLOD Zh.
Published: April 2010

We study Schrödinger equation with degenerated symmetric but not self-adjoint Hamiltonian. The above properties of the quantum Hamiltonian arise in the description of the asymptotic behavior of the regularizing self-adjoint Hamiltonians sequence. A quantum dynamical semigroup corresponding to degenerated Hamiltonian is defined by means of the passage to the limit for the sequence of the regularizing dynamical semigroups. These semigroups are generated by the regularizing self-adjoint Hamiltonians. The necessary and sufficient conditions are obtained for the convergence of the regularizing semigroups sequence. The description of the divergent sequence of semigroups requires the extension of the stochastic process concept. We extend the stochastic process concept onto the family of measurable functions defined on the space endowed with finite additive measure. The above extension makes it possible to describe the structure of the partial limits set of the regularizing semigroups sequence.
ON THE LOW-TEMPERATURE BEHAVIOR OF THE INFINITE-VOLUME IDEAL BOSE GAS
Authors: FICHTNER KARL-HEINZ , INOUE KEI , OHYA MASANORI
Published: April 2010

In Ref. 11 clustering representations of the position distribution of the ideal Bose gas were considered. In principle that gives rise to possibilities concerning simulations of the system of positions of the particles. But one has to take into account that in case of low temperature the clusters are very large and their origins are far from a fixed bounded volume. For that reason we will consider some estimations of the influence of these clusters on the behavior of the subsystem of particles located in a fixed bounded volume. All points in the fixed bounded volume come from a bigger volume which the estimation (5.2) in Theorem 5.2 gives on average. Several numerical simulations in dimension two are shown in Sec. 5.
Selective synthesis and biological activity of triazine-porphyrins as potential anti-cancer agents
Authors: Xiao Shen-Chu , Liu Chao-Zhou , Liu Wu-Kun , Xie Wen-Zhong , Lin Wei-Ying , Jiang Guo-Fang , Guo Can-Cheng
Published: April 2010

Ten new triazine-porphyrin derivatives were synthesized using a simple one-pot procedure from the reaction of tetraphenylporphyrin bearing a hydroxyl group with 2,4,6-trichloro-1,3,5-triazine, and then with amines or alcohols. The structures of the products were characterized by 1H NMR, LC/MS, UV-vis and elemental analysis. The cytotoxic activity of the triazine-porphyrin derivatives was evaluated in vitro against MCF-7 cell. All new compounds showed similar activity against MCF-7 cells in the absence of light when compared to 5-fluorouracil and hematoporphyrin.