bluuebunny/crossref_metadata_2025 huggingface dataset:
Cardiovascular and Endothelial Effects of Fish Oil Supplementation in Healthy Volunteers
Authors: Prabodh Shah Atman , Ichiuji Anne Marie , Han Janet K. , Traina Mahmoud , El-Bialy Adel , Kamal Meymandi Sheba , Yvonne Wachsner Robin
Published: September 2007

Consumption of fish oil (FO) is associated with reduced adverse cardiovascular events. In a randomized, blinded, placebo-controlled trial, 26 subjects (17 men and 9 women; mean age [± SD] 31 ± 3.7 years) received 1 g FO capsule (n = 14) or placebo (1 g of corn oil, n = 12) for 14 days. At day 0 and day 14, heart rate (HR), blood pressure, endothelium-dependent brachial artery flow-mediated vasodilation (EDV), and endothelium-independent nitroglycerin-mediated vasodilation (EIDV) were assessed with ultrasound. FO supplementation resulted in a significant increase in EDV (20.4% ± 13.2% vs 9.9% ± 5.4%; P = .036) and EIDV (32.6% ± 16.8% vs 18.0% ± 14.9%; P = .043). Resting HR decreased by a mean of 5.9 ± 9.4 bpm (FO) compared with placebo (mean increase of 0.73 ± 4.8 bpm [ P = .05]). FO supplementation in healthy subjects is associated with improved endothelial function and decreased resting HR.
Tissue ACE Inhibitors for Secondary Prevention of Cardiovascular Disease in Patients With Preserved Left Ventricular Function: A Pooled Meta-analysis of Randomized Placebo-controlled Trials
Authors: Saha Sandeep A. , Molnar Janos , Arora Rohit R.
Published: September 2007

Objective. A pooled meta-analysis of published, randomized placebo-controlled clinical trials to evaluate the role of tissue angiotensin-converting enzyme (ACE) inhibitors in secondary prevention of cardiovascular disease in patients with preserved left ventricular function. Sources. Peer-reviewed journals listed in Index Medicus/MEDLINE, the Cochrane Central Register of Controlled Clinical Trials, and the Cochrane Database of Systematic Reviews. Study selection . Randomized placebo-controlled clinical trials of at least 12 months' duration, in patients with a prior cardiovascular event or at high risk for cardiovascular events, were analyzed. Data synthesis and analysis. A total of 31 555 patients (136 882 patient-years) from 4 trials were selected for the meta-analysis. Relative risk estimations were made using data pooled from these trials, and statistical significance was determined using the χ2 test. The number of patients needed to treat was also calculated for each outcome. Results. Tissue ACE inhibitors significantly reduced the risk of all-cause mortality, cardiovascular mortality, acute myocardial infarction, and stroke ( P < .001 for each). The need for invasive coronary revascularization was reduced ( P = .03), as was the risk of hospitalization for congestive heart failure ( P = .001). The occurrence of new-onset diabetes was also significantly reduced ( P < .001), but the risk of hospitalization for angina was not significantly affected ( P = .677). Treating about 100 patients for about 4.5 years would prevent 1 death, 1 non-fatal myocardial infarction, 1 cardiovascular death, or 1 invasive coronary revascularization. Conclusions. Tissue ACE inhibitors have demonstrated benefit when used for secondary prevention of cardiovascular disease in patients with preserved left ventricular function in randomized placebo-controlled clinical trials.
Academic Hospitality
Authors: Phipps Alison , Barnett Ronald
Published: September 2007

Academic hospitality is a feature of academic life. It takes many forms. It takes material form in the hosting of academics giving papers. It takes epistemological form in the welcome of new ideas. It takes linguistic form in the translation of academic work into other languages, and it takes touristic form through the welcome and generosity with which academic visitors are received. These forms intersect each other and may co-exist at any one time. In the midst of the different forms of academic hospitality other matters surface. What is at stake when we give and receive academic hospitality? With travel being increasingly commonplace in academic life what forms of welcome and of hosting are emerging? Who is welcomed with open arms and who is not? What are the proper limits of academic hospitality? What of the stranger in our midst? What is the language of hospitality? What of virtual academic hospitality? What are the rules of the ceremonies of academic welcome? And what of the academic guest? How might we understand the modes and forms of academic hospitality? This article examines recent theories of hospitality and academic life in order to assess the potential, the rules and the limits for hospitality in an academy subject to rapid change and movement of ideas, bodies and space.
Doing SoTL in Medieval History A cross-Atlantic dialogue
Authors: Gunn Vicky , Shopkow Leah
Published: September 2007

This article, presented as a dialogue between the authors, explores what they perceive as critical areas of teaching and learning in the discipline of Medieval Studies. Within the discussion, notions of relevance and usefulness, widening access, and epistemological assumptions about the discipline are discussed and related to the practice of teaching the subject. The authors reflect on these notions in terms of the maintenance of traditional methods at undergraduate level despite an apparently changing student body. The question of whether changing the methods of research as well as teaching would alter both the nature of learning and the nature of the discipline is also raised. The authors conclude that the SoTL (scholarship of teaching and learning) of an established subject area such as Medieval Studies needs to reflect on the epistemology of the subject in all its practices, not just teaching but also research methods.
Fusing Horizons — A Grammatical Design Approach for the Arts and Humanities
Authors: Bruton Dean
Published: September 2007

This article argues that grammatical thinking within a framework of phenomenological hermeneutics assists designing and may properly be used as a fundamental teaching approach for an interdisciplinary art and design studio. Furthermore, it argues that the theme of grammatical design awareness could be considered as a generic issue across all disciplines in the Arts and Humanities. It calls for a more explicit teaching of grammar, both in terms of understanding and application, and provides a case study to indicate how this might be achieved. It highlights the value of both schematic and formal systems when using notions of rules, grammar and contingency to assist and augment traditional pedagogical approaches used in design education. It recognizes the value of grammatical visual thinking and argues that an interdisciplinary `grammatical design studio' may provide a valuable foundation for the development of design thinking processes that offer transparency, consistency, creativity and reflectivity.
The Internationalization of History Teaching through the Scholarship of Teaching and Learning Creating institutions to unite the efforts of a discipline
Authors: Pace David
Published: September 2007

Over the past decade historians and educational researchers in the UK, Australia, the USA and Canada have been devoting ever increasing energy to the systematic exploration of the learning of history at the college level. Now members of the discipline have come together to nurture and to disseminate this new scholarship of teaching and learning history. They have created an international society, a website, and an electronic newsletter that should be of interest to those in other disciplines who are concerned with bringing some of the rigor they honor in traditional research to the problems they face in the classroom.
Lighting for subsidiary streets: investigation of lamps of different SPD. Part 1—Visual Performance
Authors: Fotios SA , Cheal C.
Published: September 2007

British Standard BS5489-1: 2003 permits a trade-off between colour rendering and illuminance for lighting in subsidiary streets—if lamps of high colour rendering index such as metal halide are used instead of high- or low-pressure sodium lamps, a lower average illuminance can be used. A series of tests are carried out under mesopic conditions to validate the trade-off, and this paper reports on the new visual performance results. Four tests are carried out: acuity of achromatic and chromatic targets, achromatic contrast detection threshold, and colour identification, these being for on-axis targets. It is found that spectral power distribution (SPD) does not affect the performance of achromatic tasks except for an increase in contrast detection threshold under low-pressure sodium lamps. The performance of an acuity task using coloured targets displayed interaction between target colour and SPD. Colour naming accuracy is found to be significantly higher for metal halide lamps than for sodium lamps. For all tasks there is a reduction in visual performance at lower illuminances, and therefore a reduction in design illuminance leads to a reduction in the performance of some visual tasks which may not be offset by lamp SPD. Implications for the performance of real pedestrian tasks are discussed.
The effect of coated glazing on visual perception: A pilot study using scaleamodels
Authors: Dubois Marie-Claude , Cantin François , Johnsen Kjeld
Published: September 2007

A pilot study for investigating the effect of six coated glazing materials on visual perception of the interior and of the view out in scaled rooms is presented. The study, which involved 18 subjects, is carried out in Hørsholm (Denmark, lat. 55.4°N), under overcast skies and a north orientation. The methodology involves subjective ratings using a questionnaire and seven grade bipolar scales. The results of the statistical analysis (ANOVA) show that despite significant amplitude in daylight transmittance (50%—79%), the glazing type did not have any statistically significant effect on the perception of the sharpness of shadows in the room. It is also found that higher transmittance glazing (77%—79%) resulted in views that are more glaring compared with the views obtained with the other glazing types. In terms of light level, the reference glazing (which contained an iron-free pane) results in statistically significant differences in the ratings (brighter room) compared with the ratings from all glazing types, including glazing types of similar transmittance. Finally, it is found that higher transmittance glazing types result in more positive ratings for factors, such as naturalness, beauty, and pleasantness and sharpness.
Simplified BRDF of a Non-Lambertian Diffuse Surface
Authors: Earp A. , Smith G. , Franklin J.
Published: September 2007

For real diffuse surfaces, the bi-directional reflectance distribution function (BRDF) is non-Lambertian, and may require a more complex model in ray tracing simulations. The BRDF of a diffuse white surface is studied at multiple angles of incidence, and an additional reflectance component is observed, which becomes more specular as the angle of incidence increases. For angles of incidence >85°, the BRDF may be regarded as specular. In this article, a two-part model is proposed in which the BRDF of a diffuse surface consists of a Lambertian diffuse component and a Lorentzian pseudo-specular component — both of which vary with angle of incidence. This model may be used to reduce computation times for ray tracing simulations, as an alternative to large three-dimensional BRDF datasets.
Lighting for subsidiary streets: investigation of lamps of different SPD. Part 2—Brightness
Authors: Fotios S.A. , Cheal C.
Published: September 2007

British Standard BS5489-1: 2003 permits a trade-off between colour rendering and illuminance for lighting in subsidiary streets—if lamps of high colour rendering index are used, such as metal halide instead of low- and high-pressure sodium, a lower illuminance can be used. A series of tests are carried out to validate the trade-off and this paper reports on the new brightness data from these tests. The experimental results support the trade-off but it is suggested that its application may depend on the stage of chromatic adaptation at which the assessment of brightness is made. The experimental results are compared with predictions made by four models of mesopic photometry.
Single autologous stem-cell transplantation followed by maintenance therapy with thalidomide is superior to double autologous transplantation in multiple myeloma: results of a multicenter randomized clinical trial
Authors: Abdelkefi Abderrahman , Ladeb Saloua , Torjman Lamia , Othman Tarek Ben , Lakhal Amel , Romdhane Neila Ben , Omri Halima El , Elloumi Moez , Belaaj Hatem , Jeddi Ramzi , Aissaouï Lamia , Ksouri Habib , Hassen Assia Ben , Msadek Fahmi , Saad Ali , Hsaïri Mohamed , Boukef Kamel , Amouri Ahlem , Louzir Hechmi , Dellagi Koussay , Abdeladhim Abdeladhim Ben
Published: September 2007

From April 2003 to December 2006, 195 patients with de novo symptomatic myeloma and younger than 60 years of age were randomly assigned to receive either tandem transplantation up front (arm A, n = 97) or one autologous stem-cell transplantation followed by a maintenance therapy with thalidomide (day + 90, 100 mg per day during 6 months) (arm B, n = 98). Patients included in arm B received a second transplant at disease progression. In both arms, autologous stem-cell transplantation was preceded by first-line therapy with thalidomide-dexamethasone and subsequent collection of peripheral blood stem cells with high-dose cyclophosphamide (4 g/m2) and granulocyte colony stimulating factor. Data were analyzed on an intent-to-treat basis. With a median follow-up of 33 months (range, 6–46 months), the 3-year overall survival was 65% in arm A and 85% in arm B (P = .04). The 3-year progression-free survival was 57% in arm A and 85% in arm B (P = .02). Up-front single autologous transplantation followed by 6 months of maintenance therapy with thalidomide (with second transplant in reserve for relapse or progression) is an effective therapeutic strategy to treat multiple myeloma patients and appears superior to tandem transplant in this setting. This study was registered at www.ClinicalTrials.gov as (NCT 00207805).
Predictions of non-equilibrium phase transition in a model low-pressure steam turbine
Authors: Gerber A. G. , Sigg R , Völker L , Casey M. V. , Sürken N
Published: September 2007

An Eulerian-Eulerian multi-phase computational fluid dynamics model for predicting phase transition under non-equilibrium conditions in the low-pressure stages of a steam turbine is presented. In a novel way the model introduces dispersed liquid phases into the solution according to phase transition type and location in the turbine. Such an approach provides added information on the location and extent of phase transition regions, including associated droplet size, number, and wetness distributions. The model provides a mass weighted size distribution throughout the turbine with a resolution depending on the number of phases chosen. The study presents examples of the models usefulness in isolating phase transition activity and growth at design and off-design conditions. Comparison against results based on equilibrium phase transition in the turbine is provided for verification and discussion. Validation against measured droplet and flow data from the model turbine is also discussed.
Fast response aerodynamic probes for measurements in turbomachines
Authors: Brouckaert J. F.
Published: September 2007

The present paper concentrates on the use of single- and multi-sensor pressure probes designed for the accurate measurement of unsteady total pressure and flow angle for turbo-machinery applications. Fast response pressure probes have the advantage of offering a high analogue bandwidth, a high signal-to-noise ratio, and a good reliability and robustness as compared to hot-wire techniques for instance. In addition to the magnitude and direction of the flow velocity vector, aerodynamic probes also indicate the total and static pressure as time-resolved quantities. Appropriate data processing then allows to retrieve not only the steady, but also the periodic and random components of the measured variables.

The design of several single or multi-sensor probes is briefly described in this paper. These probes have been developed, manufactured and fully calibrated at the von Karman Institute to be used in laboratory and in industry environments over the last 8 years. The main objective of this contribution is to address some examples of applications but focus on the capabilities of the technique rather than on flow field analysis.
Influence of external geometrical modifications on the flow behaviour of a rotor-stator system: Numerical and experimental investigation
Authors: Debuchy R , Gatta S. Della. , D'Haudt E , Bois G , Martelli F
Published: September 2007

Earlier experimental and numerical studies have shown the sensitiveness of flow behaviour inside a rotating disc system due to peripheral geometry adjustments. In an opened annular cavity without any superimposed flow, velocity, and pressure levels are strongly affected by a very weak variation of the γ parameter, based on the radii difference between the two discs.

The aim of the present work is to improve knowledge of the influence of this parameter with the help of numerical simulations performed with the CFD Fluent code and experimental results carried out by hot-wire anemometry and three-holes pressure probe.

At the periphery, centrifugal effects of the rotor drive the fluid out of the cavity, imposing flow compensation on the stator side. Peripheral geometry influences the source of the inlet fluid and the inlet/outlet area ratio: these are two major elements conditioning the pre-swirl of the fluid at the periphery, which seems to control the flow behaviour inside the cavity.

One major consequence is that the well-known Batchelor type flow is not always encountered in the inner part of the cavity: it may gradually appear over a range of the λ parameter specific to geometrical conditions of the inlet.
Total pressure loss minimization in turbomachinery cascades using a new continuous adjoint formulation
Authors: Papadimitriou D. I. , Giannakoglou K. C.
Published: September 2007

A new continuous adjoint formulation for the optimization of cascade aerofoils with minimum total pressure losses, i.e. an objective function which has never been used before along with the continuous adjoint, is presented. To support a steepest descent algorithm, the adjoint method is used to compute the gradient of the objective function with respect to the design variables. The function is defined as the difference in total pressure between the inlet to and the outlet from the cascade. In contrast to other known continuous adjoint approaches in aerodynamics (such as inverse designs based on target pressure distributions or drag-lift optimization for isolated aerofoils), where the functional is defined over the parameterized solid walls, the present functional consists of integrals over the inlet/outlet boundaries only. To cope with this particular situation, the method of characteristics is used to impose inlet/outlet adjoint boundary conditions. It is worth noting that the objective function gradient is expressed as an integral over the solid walls. The minimization of losses in linear and peripheral compressor cascades, constrained by the desirable flow turning and the minimum allowed blade thickness, are demonstrated.
Advanced evaluation of transient heat transfer experiments using thermochromic liquid crystals
Authors: Poser R , von Wolfersdorf J , Lutum E
Published: September 2007

An advanced evaluation method for transient heat transfer experiments using thermochromic liquid crystals (TLCs) combining the advantages of standard hue and maximum intensity methods is presented. In order to obtain a global evaluation of locally correct heat transfer coefficients by using the one-dimensional solution of Fourier's equation, assuming heat conduction in a semi-infinite medium with a convective boundary condition, local input values have to be identified from measurements of the fluid and surface temperatures. For that reason, two different approaches have emerged. First, a two-dimensional numerical method has been adapted to evaluate the transient fluid temperature distributions in multi-pass systems from a few local measurements. Additionally, on the basis of latest calibration and indication experience of TLCs, especially in complex passages, an innovative temporal indication analysis method using a neural network has been implemented in the process of heat transfer evaluation.
Numerical simulation of the flow in a Pelton turbine using the meshless method smoothed particle hydrodynamics: A new simple solid boundary treatment
Authors: Marongiu J. C. , Leboeuf F , Parkinson E
Published: September 2007

Meshless methods are getting more and more popular in order to numerically simulate physical phenomena where an interface appears and plays an important role. Thanks to its fully Lagrangian formalism, the smoothed particle hydrodynamics method (SPH) is hence well suited to simulate free surface flows. The Pelton turbine is an hydraulic turbomachinery whose flow is challenging to simulate because of the complex rotating geometry, the free surface and the interaction between the runner and the casing. The work presented here aims at adapting SPH to simulate such a flow.

The standard SPH model has first been successfully used to prove the capacity of the method in order to simulate flows in Pelton turbines. As the prediction of the pressure field on the bucket's surface is a key issue, a new simple model for the treatment of solid boundary conditions is proposed. Simulations of industrial test cases, including a complete rotating runner, are finally shown.
Tip clearance effect on high-pressure compressor stage matching
Authors: Domercq O , Escuret J-F
Published: September 2007

Tip clearance flows have a major impact on both performance and stability of high-pressure compressors (HPC). The purpose of this paper is to underline how tip clearance variations affect the matching of compressor stages, hence modifying the efficiency and stall margin of the compressor. The practical application covered by the scope of this article is a modern highly loaded HPC dedicated to civil aircraft propulsion.

The first part of the paper gives a very simple overview of stagewise matching in multistage compressors. Also, this part introduces the subject of the impact of tip clearance on stage matching.

The second part of the paper illustrates the effect of increased rear block clearances on performance and stability, using some available experimental data. Finally, it is shown that three-dimensional multi-stage calculations can predict the effect of tip clearance variations on stage pressure-rise characteristics and on stage matching. This validated numerical tool therefore allows the aerodynamic design to be adjusted to the range of in-service clearances, thus providing a more robust compressor design.
Fair Payments for Efficient Allocations in Public Sector Combinatorial Auctions
Authors: Day Robert W. , Raghavan S.
Published: September 2007

Motivated by the increasing use of auctions by government agencies, we consider the problem of fairly pricing public goods in a combinatorial auction. A well-known problem with the incentive-compatible Vickrey-Clarke-Groves (VCG) auction mechanism is that the resulting prices may not be in the core. Loosely speaking, this means the payments of the winners could be so low, that there are bidders who would have been willing to pay more than the payments of the winning bidders. Clearly, this “unfair” outcome is unacceptable for a public sector auction. Recent advances in auction theory suggest that combinatorial auctions resulting in efficient outcomes and bidder-Pareto-optimal core payments offer a viable practical alternative to address this problem.

This paper confronts two critical issues facing the bidder-Pareto-optimal core payment. First, motivated to minimize a bidder's ability to benefit through strategic manipulation (through collusive agreement or unilateral action), we demonstrate the strength of a mechanism that minimizes total payments among all such auction outcomes, narrowing the previously broad solution concept. Second, we address the computational difficulties of achieving these outcomes with a constraint-generation approach, promising to broaden the range of applications for which bidder-Pareto-optimal core pricing achieves a comfortably rapid solution.
The Fragility of Time: Time-Insensitivity and Valuation of the Near and Far Future
Authors: Ebert Jane E. J. , Prelec Drazen
Published: September 2007

We propose that the temporal dimension is fragile in that choices are insufficiently sensitive to it, and second, such sensitivity as exists is exceptionally malleable, unlike other dimensions such as money, which are attended by default. To test this, we axiomatize a “constant-sensitivity” discount function, and in four studies, we show that the degree of time-sensitivity is inadequate relative to the compound discounting norm, and strongly susceptible to manipulation. Time-sensitivity is increased by a comparative within-subject presentation (Experiment 1), direct instruction (Experiment 3), and provision of a visual cue for time duration (Experiment 4); time-sensitivity is decreased using a time pressure manipulation (Experiment 2). In each study, the sensitivity manipulation has an opposite effect on near-future and far-future valuations: Increased sensitivity decreases discounting in the near future and increases discounting in the far future. In contrast, such sensitivity manipulations have little effect on the money dimension.
Ranking Contingent Monitoring Systems
Authors: Fagart Marie-Cécile , Sinclair-Desgagné Bernard
Published: September 2007

This paper seeks to provide a ranking of information systems in a setting of contingent monitoring. Control strategies that make the acquisition of additional information conditional on observing certain outcomes largely elude the existing ranking criteria. We show that this happens because contingent monitoring involves more than the classical trade-off between risk sharing and incentives; it also requires a balancing of incentives and downside risk. We then develop a refinement of the most common information system orderings that conveys this feature. This allows us to reinterpret and generalize some of the literature's key results concerning, for instance, auditing policies with independent or with correlated signals and monitoring systems where the precision of an added signal is endogenous.
Should Price Increases Be Targeted?—Pricing Power and Selective vs. Across-the-Board Price Increases
Authors: Krishna Aradhna , Feinberg Fred M. , Zhang Z. John
Published: September 2007

Firms in many industries experience protracted periods of pricing power, the ability to successfully enact price increases. In these situations, firms must decide not only whether to raise prices, but to whom. Specifically, in a competitive context, they must determine whether it is more profitable to increase prices across-the-board or to a specific segment of their customer base. While selective price decreases are ubiquitous in practice (e.g., better deals to potential new customers by phone carriers; better deals to current customers by various magazines), to our knowledge selective price increases are relatively rare.

We illustrate the benefits of targeted price increases, and, as such, we expand the repertoire of firms' promotional policies. To that end, we explore a scenario where two competing firms must decide whether to increase prices to the entire market or only to a specific segment. Targeted price increases (TPI), i.e., being offered an unchanged price (selectively) when others are subject to price increases, can be offered to Loyals (those who bought from the firm in the previous period) or Switchers (those who did not). The effects of TPIs are estimated through a laboratory experiment and an associated stochastic model, each allowing for both rational (Loyalty, Switching) and behaviorist (Betrayal, Jealousy) effects.

We find that TPIs can indeed yield beneficial results (greater retention for Loyals or greater attraction of Switchers) and greater profits in certain circumstances. Results for TPI are additionally benchmarked against those for targeted price decreases and are found to differ. The range of effects stemming from the experiment can be used in a competitive analysis to yield equilibrium strategies for the two firms. In this case, we find that—depending on the magnitude of the price increase, market shares of the two firms, and price knowledge across consumer segments—a firm may wish to embrace targeted price increases in some situations, to institute across-the-board price increases in others, and to not enact any price increases in still others. We show that a firm can sacrifice considerable profit if it settles on a suboptimal pricing strategy (e.g., wrongly instituting an across-the-board increase), favors the wrong segment (e.g., Switchers instead of Loyals), or ignores “behaviorist” effects (Betrayal or Jealousy).
The Effect of Digital Sharing Technologies on Music Markets: A Survival Analysis of Albums on Ranking Charts
Authors: Bhattacharjee Sudip , Gopal Ram D. , Lertwachara Kaveepan , Marsden James R. , Telang Rahul
Published: September 2007

Recent technological and market forces have profoundly impacted the music industry. Emphasizing threats from peer-to-peer (P2P) technologies, the industry continues to seek sanctions against individuals who offer a significant number of songs for others to copy. Combining data on the performance of music albums on the Billboard charts with file sharing data from a popular network, we assess the impact of recent developments related to the music industry on survival of music albums on the charts and evaluate the specific impact of P2P sharing on an album's survival on the charts. In the post-P2P era, we find significantly reduced chart survival except for those albums that debut high on the charts. In addition, superstars and female artists continue to exhibit enhanced survival. Finally, we observe a narrowing of the advantage held by major labels. The second phase of our study isolates the impact of file sharing on album survival. We find that, although sharing does not hurt the survival of top-ranked albums, it does have a negative impact on low-ranked albums. These results point to increased risk from rapid information sharing for all but the “cream of the crop.”
An Integrated Model for Hybrid Securities
Authors: Das Sanjiv R. , Sundaram Rangarajan K.
Published: September 2007

We develop a model for pricing securities whose value may depend simultaneously on equity, interest-rate, and default risks. The framework may also be used to extract probabilities of default (PD) functions from market data. Our approach is entirely based on observables such as equity prices and interest rates, rather than on unobservable processes such as firm value. The model stitches together in an arbitrage-free setting a constant elasticity of variance (CEV) equity model (to represent the behavior of equity prices prior to default), a default intensity process, and a Heath-Jarrow-Morton (HJM) model for the evolution of riskless interest rates. The model captures several stylized features such as a negative relation between equity prices and equity volatility, a negative relation between default intensity and equity prices, and a positive relationship between default intensity and equity volatility. We embed the model on a discrete-time, recombining lattice, making implementation feasible with polynomial complexity. We demonstrate the simplicity of calibrating the model to market data and of using it to extract default information. The framework is extensible to handling correlated default risk and may be used to value distressed convertible bonds, debt-equity swaps, and credit portfolio products such as collateralized debt obligations (CDOs). Applied to the CDX INDU (credit default index–industrials) Index, we find the S&P 500 index explains credit premia.
Welding of Thermoplastic Roofing Membranes Subjected to Different Conditioning Procedures
Authors: Graveline Stanley
Published: September 2007

The use of thermoplastic roofing membranes has grown dramatically over the past years. This has occurred for a number of reasons including the proven track record of some products, the move to light colored “cool” materials, and the variety of systems available. A key benefit of thermoplastic membranes is the ability to hot air weld their seams, creating a permanent seal. As these single-ply membranes are installed in a one-ply configuration, a properly executed seam is critical to their long-term performance. Welding properties of membranes from five different manufacturers of thermoplastics: two polyvinyl chloride (PVC), two thermoplastic olefins (TPO), and one KEE (ketone ethylene ester) were studied. All materials were welded at twelve different combinations of welding temperature and speed. Each of these “welding windows” was completed with material as received, after 4 days immersed in water and after 30 days of exposure to severe soiling. Finished welds were assessed by peel testing in a tensile test apparatus. Differences in welding properties of specific materials and the generic types of products were evaluated, including sensitivity to changes in weld parameters, the effectiveness of manufacturer recommended cleaning/seam preparation, as well as the impact of the conditioning processes on weld quality. Integrating a previous study by others, a weld safety factor concept was developed which is a useful metric for assessing weld quality. This work demonstrated the need for clear, product specific welding guidelines for both new materials and for roof membranes exposed to the elements so as to ensure a proper weld.
The quasicrystalline transformation in the AlCr system
Authors: Lilienfeld D.A. , Nastasi M. , Johnson H.H. , Ast D.G. , Mayer J.W.
Published: September 2007

Amorphous Al80Cr20 films were made by coevaporation and by room temperature ion irradiation of the coevaporated films. The amorphous phase was transformed into the quasicrystalline state through two routes: thermal and ion beam assisted anneal. The intensity of the quasicrystalline electron diffraction pattern increases continuously within the annealing temperature range from 547°to 607°C. The starting state of the films (as-deposited or ion-irradiated codeposited) had no effect on the thermal transformation to the quasicrystalline state. Ion irradiation of the amorphous phase at 200°C produces a more complete set of icosahedral diffraction lines. Icosahedral AlCr has the same reciprocal lattice spacings as icosahedral AlMn.
Mechanisms and kinetics of ion implantation
Authors: Lam Nghi Q. , Leaf Gary K.
Published: September 2007

The evolution of the implant distribution during ion implantation at elevated temperatures has been theoretically studied using a comprehensive kinetic model. In the model foreign atoms, implanted into both interstitial and substitutional sites of the host lattice, could interact with implantation-induced point defects and with extended sinks such as the bombarded surface. The synergistic effects of preferential sputtering, radiation-enhanced diffusion, and radiation-induced segregation, as well as the influence of nonuniform defect production, were taken into account. The bombarded surface was allowed to move in either direction, − x or + x, depending on ion energy, i.e., on the competition between the rates of ion deposition and sputtering. The moving surface was accounted for by means of a mathematical technique of immobilizing the boundary. The ion implantation process was cast into a system of five coupled partial differential equations, which could be solved numerically using a suitable technique. Sample calculations were performed for two systems: Si+ and Al+ implantations into Ni. It has been known from previous studies that in irradiated Ni, Si atoms segregate in the same direction as the defect fluxes, whereas Al solutes migrate in the opposite direction. Thus the effects of different segregation mechanisms, as well as the influence of target temperature, ion energy, and implantation rate on the evolution of implant concentrations in time and space, could be examined with the present model.
Stability and formation of NiAl3 under ion irradiation
Authors: Nastasi M. , Johnson H.H. , Mayer J.W. , Williams J.M.
Published: September 2007

Compound samples of NiAl3 as well as Ni23Al77 multilayered samples have been irradiated by either Xe or Ne ions to doses of 2 × 1015 Xe ions/cm2 and 1.3 × 106 Ne ions/cm2 at temperatures of 100 K, 300 K, and 373 K. In the case of compound irradiation, NiAl3 stability appears to be determined by regrowth kinetics and increased with lighter irradiating ion mass and higher irradiation temperature. The formation of NiAl3 by ion mixing Ni/Al multilayers was not affected by irradiating ion mass and appears to be limited by nucleation.
Self-propagating high-temperature synthesis of the SiC
Authors: Yamada Osamu , Miyamoto Yoshinari , Koizumi Mitsue
Published: September 2007

Self-propagating high-temperature synthesis (SHS), also called combustion synthesis, is useful for fabricating numerous ceramics. In the case of SiC, heat released from the exothermic reaction is not sufficient to completely convert the mixed reactants of constituent elements into SiC in the usual nonadiabatic experimental system. This disadvantage could be overcome by a new ignition process called, the “direct passing method of electric current.” By using this method, stoichiometric fine SiC powder could be obtained rapidly and efficiently with low electric power. This paper also involves the effect of particle size of Si and C initial reactant powders on conversion efficiency into SiC and also on particle size of SiC powder fabricated by this method.
Novel metal oxides prepared by ingenious synthetic routes
Authors: Rao C.N.R. , Gopalakrishnan J. , Vidyasagar K. , Ganguli A.K. , Ramanan A. , Ganapathi L.
Published: September 2007

Several novel oxides have been prepared by the decomposition of carbonate precursors of calcite structure of the general formulas Mn1−xMxCO3 (M = Mg,Co,Cd), Ca1−xMx'CO3, and Ca1−x−yMxMy”CO3
Electrical and optical transport in undoped and indium-doped zinc oxide films
Authors: Major S. , Banerjee A. , Chopra K.L.
Published: September 2007

Electrical conduction in undoped and indium-doped ZnO films in as-deposited, vacuum-annealed and oxygen-annealed states has been studied. The as-deposited and oxygen-annealed films contain a large density (≥ 1017 m−2) of trap states due to chemisorbed oxygen at the grain boundaries. The role of these trap states has been analyzed in terms of the grain boundary carrier trapping model. The vacuum-annealed films are free of chemisorbed oxygen, and the conduction in these films is controlled by scattering due to ionized impurities and grain boundary barriers. In the case of undoped ZnO films, intrinsic trap states at the grain boundaries also play a significant role. The optical behavior of all films in the UV and visible regions is dielectric-like and the optical bandgap shows a dependence on free carrier concentration that is controlled by a bandgap narrowing effect due to electron-electron and electron-impurity interactions as well as the Moss-Burstein effect of bandgap widening. In the IR region the optical behavior is metal-like due to free-electron effects and follows the Drude model.
Ion mixing of Ni–Pt films on Si
Authors: Sawada T. , Pai C.S. , Lau S.S. , Poker D.B. , Buchal Ch.
Published: September 2007

The reactions between bilayered Ni/Pt films and Si (100) substrates induced by thermal annealing and ion mixing were investigated. Thermal annealing of Si/Pt/Ni and Si/Ni/Pt samples led to layer reversal at low temperatures (∼ 300°to 400°C) and the formation of a ternary phase at high temperatures (∼ 700°C). These results are consistent with those reported in the literature. Ion mixing of both types of samples led to silicide formation without layer reversal. This effect is interpreted in terms of a change of moving species from metal (in thermal annealing) to Si (in ion mixing). The mixing efficiency between Pt and Ni is observed to be enhanced when Si is mixed together with these two metals.
Electrical and structural characterization of Nb-Si thin alloy film
Authors: Nava F. , Psaras P.A. , Takai H. , Tu K.N. , Valeri S. , Bisi O.
Published: September 2007

The structural and electrical properties of a Nb-Si thin alloy film as a function of temperature have been studied by Auger electron spectrometry, Rutherford backscattering spectroscopy, transmission electron microscopies, and in situ electrical resistivity and Hall coefficient measurements. The NbSi2,8 films were deposited by double electron-gun coevaporation onto oxidized silicon. For electrical measurements samples of a van der Pauw pattern were made through metallic masks. In the as-deposited state the coevaporated alloy film was amorphous. Upon annealing a precipitous drop in resistivity near 270°C has been determined to be the amorphous to crystalline phase transformation. The kinetics of the transformation has been determined by isothermal heat treatment over the temperature range of 224°C to 252°C. An apparent activation energy of 1.90 eV has been measured. The nucleation and growth kinetics in the crystallization process show a change in the power of time dependence from 5.5 to 2.4. The microstructures of films at various states of annealing have been correlated to the resistivity change. The crystalline NbSi2 shows an anomalous metallic behavior. The resistivity (p) versus temperature curve has a large negative deviation from linearity (dfl) and it approaches a saturation value (psat) as temperature increases. The resistivity data are fitted by two empirical expressions put forth to explain the resistivity behavior in A15 superconductors at low and high temperatures. One is based on the idea that ideal resistivity must approach some limiting value in the regime where the mean free path becomes comparable to the interatomic spacing and the other is based on a selective electron-phonon assisted scattering. In spite of the wide temperature range of analysis, it is not possible to choose one of them due to the fact that the best fit in both cases is nearly the same. The Hall coefficient (RH) changes sign from negative above ∼250°K to positive below ∼ 250°K.
Entropy-driven loss of gas phase group V species from gold/III-V compound semiconductor systems
Authors: Pugh John H. , Williams R. Stanley
Published: September 2007

Temperature-dependent chemical interactions between Au and nine III-V compound semiconductors (III = Al,Ga,In and V = P,As,Sb) have been calculated using bulk thermodynamic properties. Enthalpic considerations alone are insufficient to predict metal/ compound semiconductor reactivities. The entropy of vaporization of the group V elements is shown to be an extremely important driving force for chemical reactions involving the III-V's, since it enables several endothermic reactions to occur spontaneously under certain temperature and pressure conditions. Plots of either Gibbs' free energies of reaction or equilibrium vapor pressure of the group V element versus temperature are used to predict critical reaction temperatures for each of the systems studied. These plots agree extremely well with previous experimental observations of thin film reactions of Au on GaAs.
Raman scattering study of the staging kinetics in the c-face skin of pyrolytic graphite-H2SO4
Authors: Eklund P.C. , Olk C.H. , Holler F.J. , Spolar J.G. , Arakawa E.T.
Published: September 2007

Raman scattering from the ∼ 1600 cm−1 graphitic phonons is used to study the stage evolution of graphite-H2SO4 in the first ∼ 1000 Å of the bulk during electrochemical intercalation. The Raman results are compared to staging kinetics in the deep bulk studied previously by 00/ x-ray diffraction. For low cell currents, which establish quasiequilibrium conditions, the c-face surface of the highly oriented pyrolytic graphite (HOPG) in contact with the reactant rapidly changes stage index to n − 1 just as the bulk completes stage n. We conclude that the intercalant must cross the c-face plate boundary of the HOPG, probably entering at either grain boundaries, microcracks, or steps in the plate surface. During stage transitions, the Raman lines are observed to remain Lorentzian in shape, with constant width, indicating that an ordered stage n − 1 compound grows at the expense of an ordered stage n compound. In studies of partially submerged HOPG plates, the surface above the acid level is found to stage last, although the plate surface just below the acid level stages first. Lateral diffusion of the sulfate anions from regions below, to regions above the acid level, is apparently impeded for reasons that are not understood. During portions of the electrochemical reaction requiring only hydrogen rearrangement in the intercalate layers (“overcharging”), Raman spectra taken from above and below the acid level are observed to evolve in concert, indicating the protons are not similarly impeded.
Computer simulation of target link explosion in laser programmable redundancy for silicon memory
Authors: Scarfone L.M. , Chlipala J.D.
Published: September 2007

Pulses of Q-switched Nd-YAG radiation have been used to remove polysilicon target links during the implementation of laser programmable redundancy in the fabrication of silicon memory. The link is encapsulated by transparent dielectric films that give rise to important optical interference effects modifying the laser flux absorbed by the link and the silicon substrate. Estimates of these effects are made on the basis of classical plane-wave procedures. Thermal evolution of the composite structure is described in terms of a finite-difference form of the three-dimensional heat diffusion equation with a heat generation rate having a Gaussian spatial distribution of intensity and temporal shapes characteristic of commercial lasers. Temperature-dependent thermal diffusivity and melting of the polysilicon link are included in the computer modeling. The calculations account for the discontinuous change in the link absorption coefficient at the transition temperature. A threshold temperature and corresponding pressure, sufficiently high to rupture the dielectric above the link and initiate the removal process, are estimated by treating the molten link as a hard-sphere fluid. Numerical results are presented in the form of three-dimensional temperature distributions for 1.06 and 0.53 μm radiation with pulse energies 3.5 and 0.15μJ, respectively. Similarities and differences between heating effects produced by long (190 ns FWHM/740 ns duration) and short (35 ns FWHM/220 ns duration) pulses are pointed out.
Influence of strain rate on laterally confined concrete columns subjected to cyclic loading
Authors: Perry S.H. , Al-Shaikh A.H. , Cheong H.K.
Published: September 2007

This paper describes the effect of cyclic loading upon the compressive strength, the stress-strain relationship, and the energy absorption and dissipation characteristics of short concrete columns (stub columns) at various slow strain rates. Comparison is made with columns loaded monotonically at similar strain rates. The columns were confined laterally by high-tensile steel bolts, inserted horizontally in two orthogonal directions through preformed ducts; the annular space between ducts and bolts was grouted with high-strength epoxy resin. Both steel and concrete deformational response was measured. Significant enhancement of the strength and ductility of the concrete was obtained. Columns displayed large energy absorption and dissipation capacity under cyclic loading. The validity of an envelope curve to describe cyclic behavior is discussed.
Satipatthana: The Direct Path to Realization, Analayo
Authors: Cousins L. S.
Published: September 2007

Satipatthana: The Direct Path to Realization, Analayo (Birmingham: Windhorse Publications, 2003), 319 pp. £16.99/$24.95/Euro 24.95. ISBN 1 899579 54 0
The Two Truths in Chinese Buddhism, Chang-Qing Shih
Authors: Scherer Burkhard
Published: September 2007

The Two Truths in Chinese Buddhism, Chang-Qing Shih (Delhi: Motilal Banarsidass, 2004) (Buddhist Tradition Series. 55), pp. xviii, 401. Rs. 695. ISBN 81-208-2035-5