bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of the Flexural Strength of Five Adhesive Resin Cements
Authors: Pace Larry L. , Hummel Susan K. , Marker Victoria A. , Bolouri Ali
Published: January 2007

Statement of Problem: The increased use of adhesive resin cements in bonded prosthetic restorations has led to restorations debonding under function.

Purpose: This investigation evaluated the differences in the flexural strength of new adhesive resin cements as a function of specimen age and storage condition.

Materials and Methods: Four new dual‐cure cements were compared to C/B Metabond. Twenty specimens of each of the five cements were prepared in a rectangular glass mold (25 × 2 × 2 mm). The new cements were light‐activated with a 550 mW/cm2 lamp for 80 seconds on both the top and bottom surfaces. The auto‐cured cement was allowed to set according to manufacturer's directions. Half the specimens were tested immediately after curing while the other half were stored in distilled water at 37°C for 30 days. A three‐point bending test was performed using an Instron at a crosshead speed of 1 mm/min. The results were analyzed by analysis of variance and Scheffé tests ( p < 0.05) to examine the effect of specimen age and storage condition.

Results: RelyX ARC exhibited a significantly higher flexural strength compared with Calibra and Panavia F when tested immediately. The standard cement, C/B Metabond, deformed and did not fracture at the immediate test time. After storage, the flexural strength had significantly improved from the immediate test time for Calibra, Cement‐It, Panavia F, and C/B Metabond. However, there were no significant differences in the flexural strength among the cements when tested after 30 days in water at 37°C.

Conclusion: Immediately after curing, these new adhesive resin cements are not equivalent, as evidenced by the significant variability in the measured flexural strength. The distinctions among the cements diminish after aging in water, which may be due to residual polymerization or a plasticizing effect from water absorption.

Clinical Significance: When light‐cured, all the new adhesive resin cements have greater early strengths than the auto‐cured cement; however, the wide variation in immediate bending strength suggests that some cements may be more appropriate for use in high‐stress clinical situations such as resin‐bonded fixed partial dentures.
Conventional Rehabilitation of Edentulous Patients: The Impact on Oral Health‐Related Quality of Life and Patient Satisfaction
Authors: Ellis Janice S. , Pelekis Nanita D. , Thomason J. Mark
Published: January 2007

Purpose: This study examined patient satisfaction and oral health‐related impacts on the quality of life of patients restored with complete conventional or duplicate dentures.

Materials and Methods: Forty patients (aged 55 to 85 years) were assigned to receive new complete maxillary and mandibular dentures using either a conventional or duplication technique according to clinical need. Patients rated their satisfaction with their dentures on 100‐mm visual analogue scales before treatment and 1 month after delivery of their new dentures. Their oral health‐related quality of life was determined by completion of an Oral Health‐Related Impacts on Quality of Life questionnaire (OHIP‐20) at the same time points.

Results: Both groups of patients had similar satisfaction and OHIP ratings at the beginning of the study and 1 month after delivery of their new dentures. The two groups were comparable with regard to age and gender. Statistically significant improvement in the OHIP domains of functional limitation and physical and psychological disability was seen in both groups. The conventional group also showed significant improvement with regard to handicap, whereas the duplicate denture group showed significant improvement in the patients' rating of pain and psychological discomfort. Patient satisfaction improved significantly in both groups across all variables except ease of cleaning and ability to speak. The duplication technique resulted in patients being less satisfied with the esthetics of their new dentures.

Conclusion: In this study, the provision of new dentures either with a conventional technique or with a duplication technique resulted in an overall improvement in oral health‐related quality of life and satisfaction. These improvements were statistically significant for some domains, which varied depending on the technique used for construction of the new dentures. Neither technique was seen to be superior, which may be a reflection of the patients' treatment expectations at the outset. Patients' reported satisfaction with their dentures and the impact that dentures have on their quality of life may not be useful measures for determining the most appropriate technique for providing new dentures.
The Evolution of Advanced Prosthodontic Care: A 30‐Year Patient Report
Authors: Balshi Thomas J. , Balshi Stephen F. , Wolfinger Glenn J.
Published: January 2007

This clinical report demonstrates the history of a patient with progressive periodontal deterioration and illustrates how prosthodontic treatment has evolved over time. In 1974, maxillary and mandibular telescopic porcelain‐fused‐to‐gold fixed prostheses and a semi‐precision maxillary distal‐extension removable partial denture represented leading edge technology. Over time, a gradual deterioration in the patient's intraoral condition occurred secondary to chronic, inflammatory periodontal disease, failed appointments, and recurrent caries. Prosthodontic treatment was also evolving. The patient's teeth were extracted and ultimately replaced with two implant‐supported fixed prostheses. This clinical report is one example of how patients continually benefit from continued research in biology and materials science.
The functional immaturity of dendritic cells can be relevant to increased tolerance associated with cord blood transplantation
Authors: Encabo Araceli , Solves Pilar , Carbonell‐Uberos Francisco , Miñana Maria Dolores
Published: January 2007

BACKGROUND: Cord blood (CB) transplants have a significantly lower incidence of graft‐versus‐host disease (GVHD) compared to marrow or peripheral blood transplants. Because antigen‐presenting cells and regulatory T cells (Treg) are involved in transplant tolerance, this study was aimed at analyzing the distribution of dendritic cells (DCs) and CD14+ monocyte–specific subsets in CB and adult peripheral blood (APB) and comparing the ability of DCs from these two blood sources to induce CD4+ Treg.

STUDY DESIGN AND METHODS: Myeloid DCs (mDCs), plasmacytoid DCs, the CD14+ cell subsets CD14+CD16+ and CD14+CD209+, and CD4+ T cells were analyzed by fluorescence‐activated cell sorting (FACS) in whole blood. To evaluate the functionality of DCs, isolated CD3+ T cells from an adult donor were cultured with allogenic DC‐enriched fraction from CB or APB, and CD4+ Treg generation was determined by FACS. Additionally, tumor necrosis factor (TNF)‐α and interferon (IFN)‐α release by DCs was measured.

RESULTS: CB had a lesser frequency of DCs and specific CD14+ monocyte subsets than APB. After stimulation, monocytes from CB secreted less TNF‐α than those from APB. Moreover, DCs from CB exhibited a more immature phenotype and had a decreased capacity to release TNF‐α and IFN‐α than those derived from APB, but on the contrary, they were efficient inducers of CD4+ T cells with a phenotype of Treg.

CONCLUSION: The tolerogenic immunophenotype and diminished functionality of CB DCs can be important to create a microenvironment where Treg develop, that in turn may be relevant to observed lower incidence of chronic GVHD after CB transplantation.
Cardioprotective effects of acute normovolemic hemodilution in patients with severe aortic stenosis undergoing valve replacement
Authors: Licker Marc , Sierra Jorge , Kalangos Afksendiyos , Panos Aristote , Diaper John , Ellenberger Christoph
Published: January 2007

BACKGROUND: After acute normovolemic hemodilution (ANH), improvement of the rheologic conditions may contribute to optimize tissue oxygen delivery and attenuate ischemia‐reperfusion injuries. It was hypothesized that ANH would confer additional cardioprotection in patients with ventricular hypertrophy undergoing open heart surgery.

STUDY DESIGN AND METHODS: This study was a randomized controlled trial. Forty patients scheduled for elective aortic valve replacement were randomly assigned to a control group (standard care) or an ANH group (target hematocrit level of 28%). All patients were managed with standard myocardial preservation techniques (cold blood cardioplegia, anesthetic preconditioning). The outcome measures included the release of myocardial enzymes, perioperative hemodynamic changes, the need for pharmacologic cardiovascular support, and cardiac complications.

RESULTS: In the ANH group, the postoperative release of troponin I (mean peak plasma concentrations, 1.7 ng/mL; 95% confidence interval, 1.4‐2.1 ng/mL) and myocardial fraction of creatine kinase (22 U/L; range, 18‐24 U/L) was significantly lower than in the control group (3.6 [range, 3.0‐4.2] ng/mL and 45 [range, 39‐51] U/L, respectively). In addition, requirement for inotropic support was significantly lower and fewer hemodiluted patients presented adverse cardiac events. After ANH, there was a significant decrease in heart rate (−11 ± 6%) and rate‐pressure product (−16 ± 8%) until the aortic cross‐clamping time and, at the end of surgery, the circulating levels of erythropoietin (EPO) were higher than in control patients (13.6 ± 4.2 mUI/mL vs. 7.3 ± 2.4 mUI/mL; p < 0.05).

CONCLUSIONS: Besides conventional cardiac preservation techniques, preoperative ANH further attenuates myocardial injuries. Optimization of preischemic myocardial oxygen delivery and/or consumption and the postconditioning effects of endogenous EPO are potential mechanisms for ANH‐induced cardioprotection.
The Role of Organizations in Fostering Public Service Motivation
Authors: Moynihan Donald P. , Pandey Sanjay K.
Published: January 2007

In seeking to explain the antecedents of public service motivation, James Perry focuses on the formative role of sociohistorical context. This study tests Perry’s theory and examines the role that organizational factors play in shaping public service motivation, based on responses from a national survey of state government health and human service managers. The findings support the role of sociohistorical context, showing that public service motivation is strongly and positively related to level of education and membership in professional organizations. The results also underscore the significant influence of organizational institutions, indicating that red tape and length of organizational membership are negatively related to public service motivation, whereas hierarchical authority and reform efforts have a positive relationship. Therefore, public organizations have both an opportunity and a responsibility to create an environment that allows employees to feel they are contributing to the public good.
Public Service and Motivation: Does Mission Matter?
Authors: Wright Bradley E.
Published: January 2007

This study advances our understanding of employee work motivation and performance in the public sector by reinterpreting the literature on public service motivation within the psychological framework of goal theory. An empirical test of this new framework suggests that goal theory provides a strong theoretical foundation for understanding the independent contributions of task, mission, and public service to employee work motivation and performance. The importance of an organization’s mission increases employee work motivation in the public sector by making the job more important, even after controlling for the effect of performance‐related extrinsic rewards.
An Analysis of Differences in Work Motivation between Public and Private Sector Organizations
Authors: Buelens Marc , Van den Broeck Herman
Published: January 2007

This study contributes to our understanding of the differences in work motivation between the public and private sectors. Data from a survey of 3,314 private sector and 409 public sector employees in Belgium strongly confirm previous research showing that public sector employees are less extrinsically motivated. Differences in hierarchical level are more important determinants of work motivation than sectoral differences. In addition, most observed differences can be wholly or partially explained by differences in job content, not by the sector itself. Evidence is presented to show that motivational differences can be explained by a positive choice of work–life balance.
Religion, Spirituality, and the Workplace: Challenges for Public Administration
Authors: King Stephen M.
Published: January 2007

The relationship between religion and politics in the United States is a much‐studied academic area, particularly evident in political institutional and behavioral venues such as interest groups, electoral behavior, and political culture. One academic area that has not received much attention is the influence of religion on public administration. Recently, however, public administration scholars have begun to mimic their counterparts in the business world by examining the role of religion and spirituality in the public workplace, especially with regard to organizational performance, ethical behavior patterns, decision making, and the personal spiritual health of employees. This article examines the role and impact of religion and spirituality in the workplace, reviews court cases and political measures regarding religious expression in the public sector, explores a private sector model to explain the interrelationship between religion and spirituality in the public workplace, and challenges public administrators to consider the positive role that religion and spirituality can play in the public workplace.
The Continuing Evolution of Medicare Hospice Policy
Authors: Robinson Chester A. , Hoyer Thomas , Blackford Carol
Published: January 2007

This case study traces the creation and evolution of Medicare hospice policy. The Medicare hospice benefit, created in 1982, emphasizes palliative rather than curative care. It focuses on quality of life for the dying patient and family and encompasses medical, psychological, and spiritual care. Because no standard hospice care practices existed before this benefit was implemented, Medicare rules almost exclusively dictated the structure and delivery of services. Despite initial concerns about low use, spending averaged 17 percent per year between 1991 and 2001, largely driven by increased enrollment, covered days, services provided, and inflation. A rich accumulation of research studies and analyses of specific aspects of the hospice program provides an opportunity for a retrospective analysis of the program’s genesis, impact on health care delivery, and implications for future policy decisions.
Why Has Public Administration Ignored Public Education, and Does It Matter?
Authors: Raffel Jeffrey A.
Published: January 2007

Although education accounts for one‐quarter of the United States’ state and local government spending, employs one‐third of all governmental employees, and consistently ranks as a high priority of citizens, public administration has neglected public education. This article considers the neglect of public education by public administration scholars, researchers, and practitioners and documents the sparse coverage of public education in textbooks, journals, books, professional association activities, and curricula. This neglect can be attributed to public administration’s federal focus, ideological views about the relationship between public education and politics and resulting structural and organizational barriers, and the costs of overcoming these barriers. The separation limits the generalizability of public administration research and theory, harms policy development, constrains the capabilities of public administration program graduates, and impedes the success of public education. This article outlines steps needed to bring public education under the umbrella of public administration.
Federal and State Public Forest Administration in the New Millennium: Revisiting Herbert Kaufman’sThe Forest Ranger
Authors: Koontz Tomas M.
Published: January 2007

Herbert Kaufman’s 1960investigation of federal forest rangers provided important insights into administrative discretion, agency culture, and natural resource policy making. Subsequent studies of Forest Service administration have documented that agency’s change over time, mirroring broad changes in federal public administration. But little is known about state forest administration. This article describes results from a survey of line officers in 48 state forest agencies, as well as state forest statute analysis. Results indicate systematic state–federal differences in legal constraints, citizen interactions, and the forest administrators themselves. Though these differences foster state administrator decision making based on professional expertise, they do not encourage the incorporation of stakeholder views into agency policy making, nor do they yield a bureaucracy that represents a diverse constituency. State forest administrators perceive substantial external challenges to their professional discretion, but it remains to be seen whether state forest agencies will change to more closely resemble their federal counterpart.
Political Connections and Corporate Bailouts
Authors: FACCIO MARA , MASULIS RONALD W. , McCONNELL JOHN J.
Published: January 2007

We analyze the likelihood of government bailouts of 450 politically connected firms from 35 countries during 1997–2002. Politically connected firms are significantly more likely to be bailed out than similar nonconnected firms. Additionally, politically connected firms are disproportionately more likely to be bailed out when the International Monetary Fund or the World Bank provides financial assistance to the firm's home government. Further, among bailed‐out firms, those that are politically connected exhibit significantly worse financial performance than their nonconnected peers at the time of and following the bailout. This evidence suggests that, at least in some countries, political connections influence the allocation of capital through the mechanism of financial assistance when connected companies confront economic distress.
A Theory of Pyramidal Ownership and Family Business Groups
Authors: ALMEIDA HEITOR V. , WOLFENZON DANIEL
Published: January 2007

We provide a new rationale for pyramidal ownership in family business groups. A pyramid allows a family to access all retained earnings of a firm it already controls to set up a new firm, and to share the new firm's nondiverted payoff with shareholders of the original firm. Our model is consistent with recent evidence of a small separation between ownership and control in some pyramids, and can differentiate between pyramids and dual‐class shares, even when either method can achieve the same deviation from one share–one vote. Other predictions of the model are consistent with both systematic and anecdotal evidence.
Estimating the Gains from Trade in Limit‐Order Markets
Authors: HOLLIFIELD BURTON , MILLER ROBERT A. , SANDÅS PATRIK , SLIVE JOSHUA
Published: January 2007

We present a method to estimate the gains from trade in limit‐order markets and provide empirical evidence that the limit‐order market is a good market design. Using observations on order submissions and execution and cancellation histories, we estimate both the distribution of traders' unobserved valuations for the stock and latent trader arrival rates. We use the resulting estimates to compute the current gains from trade, the gains from trade in a perfectly liquid market, and the gains from trade with a monopoly liquidity supplier. The current gains are 90% of the maximum gains and 150% of the monopolist gains.
Insider Trading, News Releases, and Ownership Concentration
Authors: FIDRMUC JANA P. , GOERGEN MARC , RENNEBOOG LUC
Published: January 2007

This paper investigates the market's reaction to U.K. insider transactions and analyzes whether the reaction depends on the firm's ownership. We present three major findings. First, differences in regulation between the U.K. and United States, in particular the speedier reporting of trades in the U.K., may explain the observed larger abnormal returns in the U.K. Second, ownership by directors and outside shareholders has an impact on the abnormal returns. Third, it is important to adjust for news released before directors' trades. In particular, trades preceded by news on mergers and acquisitions and CEO replacements contain significantly less information.
When Financial Institutions Are Large Shareholders: The Role of Macro Corporate Governance Environments
Authors: LI DONGHUI , MOSHIRIAN FARIBORZ , PHAM PETER KIEN , ZEIN JASON
Published: January 2007

While financial institutions' aggregate investments have grown substantially worldwide, the size of their individual shareholdings, and ultimately their incentive to monitor, may be limited by the free‐rider problem, regulations, and a preference for diversification and liquidity. We compare institutions' shareholding patterns across countries and find vast differences in the extent to which they are large shareholders. These variations are largely determined by macro corporate governance factors such as shareholder protection, law enforcement, and corporate disclosure requirements. This suggests that strong governance environments act to strengthen monitoring ability such that more institutions are encouraged to hold concentrated equity positions.
Analyst Coverage and Financing Decisions
Authors: CHANG XIN , DASGUPTA SUDIPTO , HILARY GILLES
Published: January 2007

We provide evidence that analyst coverage affects security issuance. First, firms covered by fewer analysts are less likely to issue equity as opposed to debt. They issue equity less frequently, but when they do so, it is in larger amounts. Moreover, these firms depend more on favorable market conditions for their equity issuance decisions. Finally, debt ratios of less covered firms are more affected by Baker and Wurgler's (2002)“external finance‐weighted” average market‐to‐book ratio. These results are consistent with market timing behavior associated with information asymmetry, as well as behavior implied by dynamic adverse selection models of equity issuance.
Derivative Pricing 60 Years before Black–Scholes: Evidence from the Johannesburg Stock Exchange
Authors: MOORE LYNDON , JUH STEVE
Published: January 2007

We obtain daily data for warrants traded on the Johannesburg Stock Exchange between 1909 and 1922, and for a broker's call option quotes on stocks from 1908 to 1911. We use this new data set to test how close derivative prices are to Black–Scholes (1973) prices and to compute profits for investors using a simple trading rule for call options. We examine whether investors exercised warrants optimally and how they reacted to extensions of the warrants' durations. We show that long before the development of the formal theory, investors had an intuitive grasp of the determinants of derivative pricing.
Why Do Firms Issue Equity?
Authors: DITTMAR AMY , THAKOR ANJAN
Published: January 2007

We develop and test a new theory of security issuance that is consistent with the puzzling stylized fact that firms issue equity when their stock prices are high. The theory also generates new predictions. Our theory predicts that managers use equity to finance projects when they believe that investors' views about project payoffs are likely to be aligned with theirs, thus maximizing the likelihood of agreement with investors. Otherwise, they use debt. We find strong empirical support for our theory and document its incremental explanatory power over other security‐issuance theories such as market timing and time‐varying adverse selection.
Common Failings: How Corporate Defaults Are Correlated
Authors: DAS SANJIV R. , DUFFIE DARRELL , KAPADIA NIKUNJ , SAITA LEANDRO
Published: January 2007

We test the doubly stochastic assumption under which firms' default times are correlated only as implied by the correlation of factors determining their default intensities. Using data on U.S. corporations from 1979 to 2004, this assumption is violated in the presence of contagion or “frailty” (unobservable explanatory variables that are correlated across firms). Our tests do not depend on the time‐series properties of default intensities. The data do not support the joint hypothesis of well‐specified default intensities and the doubly stochastic assumption. We find some evidence of default clustering exceeding that implied by the doubly stochastic model with the given intensities.
Lower Salaries and No Options? On the Optimal Structure of Executive Pay
Authors: DITTMANN INGOLF , MAUG ERNST
Published: January 2007

We calibrate the standard principal–agent model with constant relative risk aversion and lognormal stock prices to a sample of 598 U.S. CEOs. We show that this model predicts that most CEOs should not hold any stock options. Instead, CEOs should have lower base salaries and receive additional shares in their companies; many would be required to purchase additional stock in their companies. These contracts would reduce average compensation costs by 20% while providing the same incentives and the same utility to CEOs. We conclude that the standard principal–agent model typically used in the literature cannot rationalize observed contracts.
Interest Rate Caps “Smile” Too! But Can the LIBOR Market Models Capture the Smile?
Authors: JARROW ROBERT , LI HAITAO , ZHAO FENG
Published: January 2007

Using 3 years of interest rate caps price data, we provide a comprehensive documentation of volatility smiles in the caps market. To capture the volatility smiles, we develop a multifactor term structure model with stochastic volatility and jumps that yields a closed‐form formula for cap prices. We show that although a three‐factor stochastic volatility model can price at‐the‐money caps well, significant negative jumps in interest rates are needed to capture the smile. The volatility smile contains information that is not available using only at‐the‐money caps, and this information is important for understanding term structure models.
The Impact of Collateralization on Swap Rates
Authors: JOHANNES MICHAEL , SUNDARESAN SURESH
Published: January 2007

Interest rate swap pricing theory traditionally views swaps as a portfolio of forward contracts with net swap payments discounted at LIBOR rates. In practice, the use of marking‐to‐market and collateralization questions this view as they introduce intermediate cash flows and alter credit characteristics. We provide a swap valuation theory under marking‐to‐market and costly collateral and examine the theory's empirical implications. We find evidence consistent with costly collateral using two different approaches; the first uses single‐factor models and Eurodollar futures prices, and the second uses a formal term structure model and Treasury/swap data.
The Value of Embedded Real Options: Evidence from Consumer Automobile Lease Contracts
Authors: GIACCOTTO CARMELO , GOLDBERG GERSON M. , HEGDE SHANTARAM P.
Published: January 2007

Under the common assumption of constant interest rates, we show that penalties for early termination of a lease are often structured in such a way that the cancellation option embedded in consumer automotive leases has little value. Furthermore, our estimates drawn from a sample of three popular car models over 1990 to 2000 indicate that the stand‐alone value of the lease‐end purchase option is, on average, about 16% of the market value of underlying used vehicles, or about $1,462 per contract. Finally, we examine the sensitivity of our option value estimates to model parameters and default risk.
Reconcilable Differences: Momentum Trading by Institutions
Authors: Sias Richard W.
Published: January 2007

A growing literature evaluates the relation between lag returns and demand by institutional investors. Given that lag returns and institutional ownership are directly observable, it is surprising that previous tests yield dramatically different conclusions. This study examines differences across studies and finds that four factors account for these discrepancies: (1) value‐weighting versus equal‐weighting across stocks, (2) averaging versus aggregating over managers, (3) disagreement in the signs of measures of institutional demand, and (4) correlation between current capitalization and both lag returns and measures of institutional demand. Controlling for these factors, the results across different methods are remarkably uniform.
The U.S. Share of Trading Volume in Cross‐Listings: Evidence from Canadian Stocks
Authors: Sabherwal Sanjiv
Published: January 2007

I analyze the firm‐specific determinants of the U.S. share of trading volume for 126 U.S.‐listed Canadian firms. I find that the U.S. share of volume is directly related to the mass of informed and liquidity traders in the United States relative to Canada, as proxied by relative analyst following, relative duration of listing, and the U.S. share of sales. Evidence also supports the market liquidity argument that the market with lower spreads and greater depths has greater volume. Finally, the U.S. share is directly related to the relative sensitivity of the stock's value to information in the United States.
Climate for Scandal: Corporate Environments that Contribute to Accounting Fraud
Authors: Crutchley Claire E. , Jensen Marlin R. H. , Marshall Beverly B.
Published: January 2007

We examine the governance characteristics, earnings quality, growth rates, dividend policy, and compensation structure of 97 firms recently under investigation by the Securities and Exchange Commission (SEC) for accounting fraud. Our results show that the corporate environment most likely to lead to an accounting scandal manifests significant growth and accounting practices that are already pushing the envelope of earnings smoothing. Firms operating in this environment seem more likely to tip over the edge into fraud if there are fewer outsiders on the audit committee and outside directors appear overcommitted.
Equity with Warrants in Private Placements
Authors: Marciukaityte Dalia , Pennathur Anita K.
Published: January 2007

We examine private equity with warrant (unit) placements and compare them with private equity placements. Firms making unit placements are smaller, younger, riskier, and characterized by higher information asymmetry than equity‐placing firms. Furthermore, unit‐placing firms experience good pre‐placement stock performance; however, their post‐placement performance is poor and worse than that of equity‐placing firms. We also find that very few of the placed warrants are in the money at expiration. Our results are consistent with the window of opportunity hypothesis and the theory that warrants are especially desirable to a clientele of overoptimistic investors.
Perceptions of Time and Their Impact on Negotiations in the Arabic‐Speaking Islamic World
Authors: Alon Ilai , Brett Jeanne M.
Published: January 2007

This article examines how perceptions of time affect Arabic‐speaking Islamic negotiators and how their attitudes about time, and their corresponding behaviors, may differ from those of their Western counterparts. We begin by identifying cultural differences in the conceptualization of time and then comment on the role of time in negotiations, discussing how time influences bargaining, trust, and negotiation tactics. In the section on tactics, we discuss stall‐and‐delay tactics, the use of the past as an objective standard, and limits on negotiating the future. Our purpose is to encourage negotiators from the West to be knowledgeable about the way they, as well as negotiators from Arabic‐speaking Islamic cultures, conceive of and use time in negotiations. We believe that understanding that the very concept of time is often quite different in these two cultures is an important step in facilitating negotiations that cross these cultural boundaries.
Results of vision screening of 6‐year‐olds at school: a population‐based study with emphasis on screening limits
Authors: Hård Anna‐Lena
Published: January 2007

Purpose:  To evaluate newly introduced vision screening of 6‐year‐olds in the preschool class with special regard to screening criteria.

Methods:  Monocular visual acuity (VA) testing in 6‐year‐olds by school nurses as part of preventive health care was introduced in Sweden 2003. Children with VA < 0.8 (logMAR 0.1) or symptoms are referred to eye clinics where VA testing, cover testing, cycloplegic autorefraction and ophthalmoscopy are performed. The present screening limit of 0.8 (logMAR 0.1) was evaluated in relation to a limit of 0.65 (logMAR 0.2). All children in the City of Gothenburg starting preschool class in 2003 were included.

Results:  A total of 127 schools with 3885 pupils participated. Of these, 255 pupils (6.6%) were referred and 236 underwent an ophthalmological examination. Children with a VA of 0.65 (logMAR 0.2) in the worse eye constituted 74.5% of those who had failed the screening; more than half of these were found to have VA ≥ 0.8 (logMAR 0.1) in the clinic. Many were not refracted in cycloplegia and only 6.7% were found to have significant ametropia. The criteria for the prescription of glasses varied; 13.4% of these children were prescribed glasses for insignificant refractive errors.

Conclusions:  Six‐year‐olds with VA of 0.65 (logMAR 0.2) rarely have defects that require treatment and the screening criterion of 0.8 (logMAR 0.1) is probably too demanding for effective utilization of available resources. Retest before referral and refraction in cycloplegia of all children with reduced VA or visual symptoms are recommended.
Associations between peri‐implant crevicular fluid volume, concentrations of crevicular inflammatory mediators, and composite IL‐1A –889 and IL‐1B +3954 genotype: A cross‐sectional study on implant recall patients with and without clinical signs of peri‐implantitis
Authors: Lachmann Stefan , Kimmerle‐Müller Evi , Axmann Detlef , Scheideler Lutz , Weber Heiner , Haas Robert
Published: January 2007

Objectives: To assess possible relationships between peri‐implant crevicular fluid (PICF) volumes, biochemical markers of the peri‐implant immune response, and periodontitis‐associated genotype.

Material and methods: PICF samples from 29 implant maintenance patients, 24 wearing overdentures, five having single crowns and bridgework (11 patients with peri‐implantitis and 18 individuals with healthy peri‐implant conditions), were analyzed for per site and per crevicular‐fluid‐volume concentrations of interleukin‐1β, plasminogen activator inhibitor type 2, and prostaglandin E2 by ELISA. Associations between the three substance concentrations and to crevicular fluid flow rate were analyzed by linear regression analysis. The possible differentiating influence of the composite interleukin‐1A and ‐1B genotype on the patients' peri‐implant health and biochemical inflammatory status was checked formally with t‐test statistics and the Wilcoxon' test. One implant per patient was chosen for analysis.

Results: In patients with healthy peri‐implant conditions, genotype‐positive individuals showed elevated crevicular fluid flow rates and at the same time reduced mediator concentrations. In patients with an implant affected from peri‐implantitis, no statistically significant influence of the periodontitis‐associated genotype around the fixture can be stated. There was no statistical difference between per site and per crevicular‐fluid‐volume concentration analyses. All three mediator concentrations were positively related to each other, while there was a strong negative correlation between crevicular fluid volume and plasminogen activator inhibitor 2 or prostaglandin E2.

Conclusions: The Interleukin‐1 polymorphism investigated exerted only little influence on the peri‐implant crevicular immune response, and this influence appeared to be of limited impact in sites with established peri‐implantitis lesions.
Platelet‐rich plasma activity on maxillary sinus floor augmentation by autologous bone
Authors: Consolo Ugo , Zaffe Davide , Bertoldi Carlo , Ceccherelli Giovanni
Published: January 2007

Objectives: This work aims to evaluate the regenerative potential of platelet‐rich plasma (PRP) on an implant site of peculiar clinical impact, such as sinus augmentation.

Material and methods: Sixteen consenting patients (11 females and five males), with symmetrical maxillary sinus atrophy, underwent bilateral sinus floor augmentation, using autologous (iliac crest) bone on one side and PRP plus autologous bone contralaterally. Implants were inserted 4, 5, 6 and 7 months after surgery in the patients randomly split into four groups. Orthopantomographies, computed tomography with transverse image digital reconstructions and densitometries were used to monitor the treatment progress. A core biopsy was performed at the site of implant.

Results: Clinical performance across both sites showed no statistical significance (P=0.414). Densitometric values were higher at PRP sites (mean Hounsfield units ∼+57%), even if densitometry converged in the two sites 8 months after surgery. Histology documents enhanced bone activities in sites treated with PRP, 4 months after surgery. Reduced bone activity was observed in both sites 5, 6 and 7 months after surgery. Bone amount, higher in sites treated with PRP (mean trabecular bone volume ∼+37%), decreased in both sites over time.

Conclusions: Our results seem to indicate a certain regenerative potential of PRP when used with autologous bone. The effect of this enhancement of bone regeneration appeared to be restricted to shorter treatment times. A progressive extinguishment of the PRP effect is recorded after an interval longer than 6–7 months.
The definition and assessment of vitiligo: a consensus report of the Vitiligo European Task Force
Authors: Taïeb Alain , Picardo Mauro ,   on behalf of the other VETF members
Published: January 2007

Vitiligo is the most common depigmenting disorder, which affects 0.5–1% of the worldwide population, causing disfigurement and serious disturbances in well being. There is a current lack of consensus in definition and methods of assessment of this disorder, which makes it generally impossible to compare the outcomes of different studies of the same treatment. This report summarizes the work carried out by the Vitiligo European Task Force to propose a consensus definition of the disease and to assess treatment outcomes using a system which combines analysis of extent, stage of disease (staging), and disease progression (spreading). In summary, extent is evaluated using the rule of 9. Staging is based on cutaneous and hair pigmentation in vitiligo patches, and the disease is staged 0–3 (revised version) on the largest macule in each body region, except hands and feet, which are assessed separately and globally as one unique area. Assessment of spreading is based on Wood's lamp examination of the same largest macule in each body area. Wood's lamp is useful for a combined assessment of staging and spreading in the same selected area. This study reports a workshop which validated the clinical use of the assessment form performed at several European University clinics, and showed an overall good concordance among panelists using the proposed scoring system. This system can be easily handled in clinical practice. However, variations between scorer profiles indicate a need for training to decrease interobserver variability. Further steps are envisaged, namely: (i) build a global index including staging and spreading for the initial assessment of vitiligo patients, usable as a guidance for therapeutic indications and prognosis, which could be interpreted as an equivalent of the TNM (tumor, node, metastasis) system for cancer; (ii) implement large‐scale tests necessary for clinical trials (to check reproducibility and sensitivity); (iii) carry out studies of automated devices to assess extent more accurately; (iv) set up a teaching tool for scoring vitiligo, which could be posted on a website; and (v) set up an international conference on classifying, staging and scoring vitiligo, through the IFPCS Special Interest Group on Vitiligo.
Fabricating a better mouthguard. Part I: Factors influencing mouthguard thinning
Authors: Del Rossi Gianluca , Leyte‐Vidal Marco A
Published: January 2007

Abstract –  There is some concern regarding the amount of material thinning that occurs during the fabrication of custom‐fabricated mouthguards. It is unclear if this thinning is merely a consequence of the fabrication process or related to other factors such as jaw size. Thus, the purpose of this study was to evaluate the contribution that various dimensional characteristics of the dental arch and the height of the stone model would have on mouthguard thinning. Fifteen subjects participated in this investigation. Alginate impressions from each subject were used to produce three replicas of the maxillary dentition with only the height of the base varying amongst them. The total height of the three models were 20, 25, and 30 mm. A single mouthguard was produced using each of the stone models. The material thickness of the mouthguard was assessed at the labial and occlusal surfaces. Additionally, the dimensions of the stone models were documented. Pearson product moment correlation coefficients were calculated to determine the linear relationship between material thickness and (i) the height of the stone models, (ii) the arch length and (iii) the area covered by the stone model. Statistical tests performed using the mean thickness values collected from the incisors and canines revealed a high negative correlation between the height of the stone model and material thickness (r = −0.82). In addition, a low to moderate positive linear correlation was noted between arch length and occlusal thickness at the molars (r = 0.57) and between the area of the stone model with the occlusal thickness (r = 0.49). The results of the present study indicate that the height of the model used to fabricate custom mouthguards should be kept as low as possible but still allow for the production of a properly fitting mouthguard.
The legacy of stockless organic conversion strategies
Authors: Rollett A.J. , Sparkes D.L. , Wilson P.
Published: January 2007

Legume‐containing leys are commonly used to improve soil fertility in the 2‐year conversion period from conventional to organic production. While in‐conversion land may be grazed, in stockless farming systems, land is effectively out of production, leading to a reduction in income and pressure on cash flow. The impacts of seven organic conversion strategies on the first organic crop (winter wheat) were previously reported. This study investigates the effect of the conversion strategies on the second (winter beans) and third (winter oats) organic crops, thereby extending the analysis throughout the first complete rotation. The strategies were (a) 2‐years’ red clover–ryegrass green manure, (b) 2‐years’ hairy vetch green manure, (c) red clover for seed production then a red clover–ryegrass green manure, (d) spring wheat undersown with red clover, then a red clover green manure, (e) spring oats, then winter beans, (f) spring wheat, then winter beans and (g) spring wheat undersown with red clover, then a barley–pea intercrop. Conversion strategy had a significant impact on organic bean yield, which ranged from 2.78 to 3.62 t ha−1, and organic oat yield, which ranged from 3.24 to 4.17 t ha−1. In the organic bean crop, weed abundance prior to harvest, along with soil texture, accounted for 70% of yield variation. For the oats, soil mineral nitrogen in November together with weed abundance in April accounted for 72% of the variation in yield. The impacts of conversion strategies on soil mineral nitrogen levels were still detectable 3 years after conversion. The results from this study indicate that the choice of conversion crop has important long‐term implications. More exploitative conversion strategies, that is those with a higher proportion of cash cropping, had an increased weed burden and decreased levels of soil mineral nitrogen, leading to reduced yields of beans and oats, 2 and 3 years after conversion.
Climate‐ameliorating measures influence photosynthetic gas exchange of apple leaves
Authors: Gindaba J. , Wand S.J.E.
Published: January 2007

Sunburn has become one of the major threats to apple fruit production in South Africa and other countries with Mediterranean climate. Some climate‐ameliorating measures have been developed to control sunburn in apples. Effects of the climate‐ameliorating measures, viz. evaporative cooling, Surround® WP and shade net, on leaf gas exchange of a 5‐year‐old orchard of ‘Cripps’ Pink’ apple were investigated during hot summer days in Stellenbosch, South Africa. Evaporative cooling increased net photosynthetic rate (A) and stomatal conductance (gs) because of its lowering of leaf temperature and leaf‐to‐air vapour pressure difference (VPD). Shade net also reduced leaf temperature because of reduction in photosynthetic photon flux density (PPFD). Quantum efficiency of photosynthesis was increased under shade net to compensate for reduced PPFD. Shade net also reduced transpiration rate more than A, resulting in increased midday water‐use efficiency. The diurnal trends of A and gs in the Surround WP and control treatments were similar, indicating limited ameliorative impact of Surround WP. Furthermore, Surround WP typically reduced maximum rate of carboxylation and the light‐saturated rate of electron transport. In all treatments, A decreased by 70% when leaf temperature increased from 35°C to 40°C. In conclusion, all treatments affected leaf photosynthetic gas exchange. Evaporative cooling enhanced leaf A and gs because of distinct ameliorative effects on leaf temperature and VPD. Shade net reduced leaf temperature with no consistent effects on leaf gas exchange attributes. Surround WP had limited or no impact on leaf temperature and negatively affected leaf gas exchange attributes.
Temperature‐dependent stomatal movement in tulip petals controls water transpiration during flower opening and closing
Authors: Azad A.K. , Sawa Y. , Ishikawa T. , Shibata H.
Published: January 2007

Temperature‐dependent tulip petal opening and closing movement was previously suggested to be regulated by reversible phosphorylation of a plasma membrane aquaporin (Azad et al., 2004a). Stomatal apertures of petals were investigated during petal opening at 20°C and closing at 5°C. In completely open petals, the proportion of open stomata in outer and inner surfaces of the same petal was 27 ± 6% and 65 ± 3%, respectively. During the course of petal closing, stomatal apertures in both surfaces reversed, and in completely closed petals, the proportion of open stomata in outer and inner surfaces of the same petal was 74 ± 3% and 29 ± 6%, respectively, indicating an inverse relationship between stomatal aperture in outer and inner surfaces of the petal during petal opening and closing. Both petal opening and stomatal closure in the outer surface of the petal was inhibited by a Ca2+ channel blocker and a Ca2+ chelator, whereas the inner surface stomata remained unaffected. On the other hand, sodium nitroprusside, a nitric oxide donor, had no effect on stomatal aperture of the outer surface but influenced the inner surface stomatal aperture during petal opening and closing, suggesting different signalling pathways for regulation of temperature‐dependent stomatal changes in the two surfaces of tulip petals. Stomata were found to be differentially distributed in the bottom, middle and upper parts of tulip petals. During petal closing, water transpiration was observed by measuring the loss of 3H2O. Transpiration of 3H2O by petals was fivefold greater in the first 10 min than that found after 30 min, and the transpiration rate was shown to be associated with stomatal distribution and aperture. Thus, the stomata of outer and inner surfaces of the petal are involved in the accumulation and transpiration of water during petal opening.