Creating a Theoretically Grounded, Gamified Health App: Lessons From Developing the Cigbreak Smoking Cessation Mobile Phone Game

Feasibility and Acceptability of a Mobile Game to Support Smoking Cessation: Repeated Measures Study

BACKGROUND

Approximately half of smokers attempt to quit, but 90% of these attempts fail. Video game-based interventions have the potential to address common barriers to evidence-based smoking cessation treatment, including high cost, lack of health care access, and low engagement.

OBJECTIVE

The purpose of this study was to evaluate the feasibility and acceptability of a video game-based smoking cessation intervention called Inspired and its impact on the 7-day smoking point prevalence at the 30-day follow-up.

METHODS

US adults (n=48) were recruited via the web to use Inspired on their smartphones for 7 weeks. The object of the game was to defend a healing tree against attackers. Levels of the game were unlocked twice daily when participants self-reported the number of cigarettes they smoked since the previous entry. Completion of the levels awarded players in-game currency, which could strengthen in-game abilities. Participants received additional in-game rewards to aid gameplay by submitting either smoking self-reports only or self-reports indicating abstinence, determined through random assignment. In addition, participants completed a web-based survey at intake, week 4, week 7, and the 30-day follow-up.

RESULTS

Of the 48 participants, who had an average age of 39.8 (SD 10.7) years, 27 (56%) were female, 4 (8%) Hispanic, 37 (77%) White, and 27 (56%) employed; 26 (54%) earned

CONCLUSIONS

These results support the acceptability of Inspired. Although high dropout rates prevent conclusions on feasibility, a subset of the participants responded favorably. Scalable and accessible video game-based smoking cessation interventions could be the key to addressing the foremost cause of preventable morbidity and mortality in the United States.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03929003; https://clinicaltrials.gov/ct2/show/NCT03929003.

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Key Words

• mHealth
• mobile health
• mobile phone
• smoking cessation
• video game intervention

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Affiliation(s)

Shelby Goodwin Department of Psychology, College of Science and Mathematics, Rowan University, Glassboro, NJ, United States
Jessica A Nastasi Department of Psychology, University of Florida, Gainesville, FL, United States
Schyler T Newman Department of Psychology, University of Missouri, St. Louis, MO, United States
Darion Rapoza Division of Cardiology, Department of Medicine, Duke University School of Medicine, Durham, NC, United States Entertainment Science, Inc, Durham, NC, United States
Bethany R Raiff Department of Psychology, College of Science and Mathematics, Rowan University, Glassboro, NJ, United States

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Developing a Game (Inner Dragon) Within a Leading Smartphone App for Smoking Cessation: Design and Feasibility Evaluation Study

BACKGROUND

Several stand-alone smartphone apps have used serious games to provide an engaging approach to quitting smoking. So far, the uptake of these games has been modest, and the evidence base for their efficacy in promoting smoking cessation is still evolving. The feasibility of integrating a game into a popular smoking cessation app is unclear.

OBJECTIVE

The aim of this paper was to describe the design and iterative development of the Inner Dragon game within Smoke Free, a smartphone app with proven efficacy, and the results of a single-arm feasibility trial as part of a broad program that seeks to assess the effectiveness of the gamified app for smoking cessation.

METHODS

In phase 1, the study team undertook a multistep process to design and develop the game, including web-based focus group discussions with end users (n=15). In phase 2, a single-arm study of Smoke Free users who were trying to quit (n=30) was conducted to assess the feasibility and acceptability of the integrated game and to establish the feasibility of the planned procedures for a randomized pilot trial.

RESULTS

Phase 1 led to the final design of Inner Dragon, informed by principles from psychology and behavioral economics and incorporating several game mechanics designed to increase user engagement and retention. Inner Dragon users maintain an evolving pet dragon that serves as a virtual avatar for the users' progress in quitting. The phase-2 study established the feasibility of the study methods. The mean number of app sessions completed per user was 13.8 (SD 13.1; median 8; range 1-46), with a mean duration per session of 5.8 (median 1.1; range 0-81.1) minutes. Overall, three-fourths (18/24, 75%) of the participants entered the Inner Dragon game at least once and had a mean of 2.4 (SD 2.4) sessions of game use. The use of Inner Dragon was positively associated with the total number of app sessions (correlation 0.57). The mean satisfaction score of participants who provided ratings (11/24, 46%) was 4.2 (SD 0.6) on a 5-point scale; however, satisfaction ratings for Inner Dragon were only completed by 13% (3/24) of the participants.

CONCLUSIONS

Findings supported further development and evaluation of Inner Dragon as a beneficial feature of Smoke Free. The next step of this study is to conduct a randomized pilot trial to determine whether the gamified version of the app increases user engagement over a standard version of the app.

Smokers' user experience of smoking cessation apps: A systematic review

OBJECTIVES

To explore how smokers view common functions and characteristics of smoking cessation apps.

DESIGN

Systematic review.

SEARCH SOURCES

CINAHL PLUS, MEDLINE, PsycINFO, EMBASE, IEEE Xplore, ACM Digital Library, and Google Scholar.

REVIEW METHODS

Seven digital databases were searched separately using relevant search terms. Search results were uploaded to Covidence. Inclusion and exclusion criteria were identified with the expert team in advance. Titles, abstracts, and full texts were screened by two reviewers independently. Any disagreements were discussed in research meetings. Pertinent data were extracted and analysed using qualitative content analysis. Findings were presented in a narrative approach.

RESULTS

28 studies were included in this review. The overarching themes were app functionality and app characteristics. Under app "functionality", six subthemes emerged: 1) education; 2) tracking; 3) social support; 4) compensation; 5) distraction, and 6) reminding. Under "app characteristics", five subthemes emerged: 1) simplification, 2) personalisation, 3) diverse content forms, 4) interactivity, and 5) privacy and security.

CONCLUSION

Understanding user needs and expectations is crucial for developing a programme theory for smoking cessation app interventions. Relevant needs identified in this review should be linked to broader theories of smoking cessation and app-based intervention.

Effectiveness of an App for tobacco cessation in pregnant smokers (TOBBGEST): study protocol

BACKGROUND

Tobacco consumption during pregnancy is one of the most modifiable causes of morbidity and mortality for both pregnant smokers and their foetus. Even though pregnant smokers are conscious about the negative effects of tobacco consumption, they also had barriers for smoking cessation and most of them continue smoking, being a major public health problem. The aim of this study is to determine the effectiveness of an application (App) for mobile devices, designed with a gamification strategy, in order to help pregnant smokers to quit smoking during pregnancy and in the long term.

METHODS

This study is a multicentre randomized community intervention trial. It will recruit pregnant smokers (200 participants/group), aged more than 18 years, with sporadically or daily smoking habit in the last 30 days and who follow-up their pregnancy in the Sexual and Reproductive Health Care Services of the Camp de Tarragona and Central Catalonia Primary Care Departments. All the participants will have the usual clinical practice intervention for smoking cessation, whereas the intervention group will also have access to the App. The outcome measure will be prolonged abstinence at 12 months after the intervention, as confirmed by expired-carbon monoxide and urinary cotinine tests. Results will be analysed based on intention to treat. Prolonged abstinence rates will be compared, and the determining factors will be evaluated using multivariate statistical analysis.

DISCUSSION

The results of this study will offer evidence about the effectiveness of an intervention using a mobile App in smoking cessation for pregnant smokers, to decrease comorbidity associated with long-term smoking. If this technology is proven effective, it could be readily incorporated into primary care intervention for all pregnant smokers.

TRIAL REGISTRATION

Clinicaltrials.gov ID NCT05222958 . Trial registered 3 February 2022.

Pilot trial of QuitBet: A digital social game that pays you to stop smoking

Contingency management is an effective treatment for cigarette smoking cessation but feasibility and acceptability concerns have been barriers to implementation. We conducted a pilot test of QuitBet, a commercial, digital (smartphone) social game for smoking cessation during which participants earned financial incentives for abstinence. QuitBet included a social feed for posting messages and entirely participant-funded incentives in the form of a deposit contract (the "bet"). QuitBet had a bet of $30 and lasted for 28 days. After a week to prepare for quitting, the quit day was Day 8. Between Day 9-28 (a 20-day period), participants earned back $1 of their $30 bet for each day of carbon monoxide (CO)-verified abstinence (≤ 6 ppm). Remaining bet money was pooled into a "grand prize" pot. Participants who were abstinent on at least 19 of the 20 days (1 "lapse" day allowed) were declared "winners" and split the grand prize pot equally. A game host posted a daily message containing evidence-based education about smoking cessation or a discussion topic. Recruitment goals were met. Among the players (N = 50 U.S. adults, 78% female), 17 (34%) were winners. Thirty-seven participants (74%) responded to a post-QuitBet survey, of whom 95% said they would be interested in playing another QuitBet and would recommend QuitBet to others. Overall, feedback was positive with some suggestions for improvement. In conclusion, a digital social game for smoking cessation with a deposit contract was feasible and acceptable. Next steps include conducting a randomized trial to establish efficacy and a sustainable business model. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Developing an alcohol and other drug serious game for adolescents: considerations for improving student engagement

OBJECTIVES

To explore perceptions of alcohol and other drug (AOD) education and digital game design preferences among Australian adolescents with the goal of identifying key factors to promote engagement in an AOD serious game for Australian secondary school students.

METHODS

Semi-structured focus groups were conducted with 36 adolescents aged between 13 and 18 years. Qualitative data was analysed using thematic analysis.

RESULTS

Participants described heightened engagement with AOD education that incorporated relatable and relevant real-life stories and interactive discussions. They also expressed a desire for learning to focus on practical strategies to reduce AOD harm and overcome social pressure to use AOD. Participants highlighted the importance of incorporating relatable characters and context-relevant scenarios in promoting engagement, and identified social elements, player choice, and optimal challenge as important game design considerations.

CONCLUSIONS

A focus on meaningful realistic scenarios, relatable characters, relevant information and practical skills may promote high school aged students' engagement with AOD educational content. Game designs incorporating social elements and decision-making opportunities may be conducive to promoting engagement and enhancing learning.

IMPLICATIONS FOR PUBLIC HEALTH

Findings from this study can be used by researchers and game designers for the development of future AOD serious games targeted at Australian adolescents.

Conceptual Ambiguity Surrounding Gamification and Serious Games in Health Care: Literature Review and Development of Game-Based Intervention Reporting Guidelines (GAMING)

BACKGROUND

In health care, the use of game-based interventions to increase motivation, engagement, and overall sustainability of health behaviors is steadily becoming more common. The most prevalent types of game-based interventions in health care research are gamification and serious games. Various researchers have discussed substantial conceptual differences between these 2 concepts, supported by empirical studies showing differences in the effects on specific health behaviors. However, researchers also frequently report cases in which terms related to these 2 concepts are used ambiguously or even interchangeably. It remains unclear to what extent existing health care research explicitly distinguishes between gamification and serious games and whether it draws on existing conceptual considerations to do so.

OBJECTIVE

This study aims to address this lack of knowledge by capturing the current state of conceptualizations of gamification and serious games in health care research. Furthermore, we aim to provide tools for researchers to disambiguate the reporting of game-based interventions.

METHODS

We used a 2-step research approach. First, we conducted a systematic literature review of 206 studies, published in the Journal of Medical Internet Research and its sister journals, containing terms related to gamification, serious games, or both. We analyzed their conceptualizations of gamification and serious games, as well as the distinctions between the two concepts. Second, based on the literature review findings, we developed a set of guidelines for researchers reporting on game-based interventions and evaluated them with a group of 9 experts from the field.

RESULTS

Our results show that less than half of the concept mentions are accompanied by an explicit definition. To distinguish between the 2 concepts, we identified four common approaches: implicit distinction, synonymous use of terms, serious games as a type of gamified system, and distinction based on the full game dimension. Our Game-Based Intervention Reporting Guidelines (GAMING) consist of 25 items grouped into four topics: conceptual focus, contribution, mindfulness about related concepts, and individual concept definitions.

CONCLUSIONS

Conceptualizations of gamification and serious games in health care literature are strongly heterogeneous, leading to conceptual ambiguity. Following the GAMING can support authors in rigorous reporting on study results of game-based interventions.

Current State of Serious Games in Dentistry: A Scoping Review

Objective: Over the past decade, serious games (SGs) have played a growing role in medical education and health promotion; however, little is known about their use in the field of oral health. This study provides a comprehensive synthesis about SGs developed for training oral health professionals or for health promotion in oral health. Material and Methods: A systematic search was conducted. The following electronic databases were reviewed: MEDLINE (1966 to September 2019), Embase (1980 to September 2019), and Cochrane Central Register of Controlled Trials (CENTRAL), LILACS and Scopus from inception to September 2019. Two reviewers independently screened and assessed the study's quality and extracted data. The Sardi and collaborators' tool was used to assess the quality of the evidence presented. Results: A total of 19 studies (25 articles) were selected. Games were divided into two categories: for specific educational purposes and for oral health promotion. Most studies involved oral health professions' students (n = 9) or school/preschool children (n = 9). Two studies included preschool children and parents. Interactive SGs were as effective as traditional noninteractive methods in improving oral health outcomes. Nonetheless, participants' feedback reflected a higher level of satisfaction in learning through games. The quality of the studies was limited due to the lack of a proper technical description of the games and the absence of discussion of the limitations and challenges of the games. Conclusion: The use of SGs in oral health is limited, and little valid empirical evidence is available to confirm their effectiveness. Further studies are required for using more rigorous designs, evaluation, and follow-ups.

Effects of a Mobile App Called Quittr, Which Utilizes Premium Currency and Games Features, on Improving Engagement With Smoking Cessation Intervention: Pilot Randomized Controlled Trial

BACKGROUND

Numerous mobile health (mHealth) apps have been developed to support smokers attempting to quit smoking. Although these apps have been reported to be successful, only modest improvements in the quit rate have been measured. It has been proposed that efforts to improve user engagement and retention may improve the quit rate further. Owing to the high cost of smoking-related disease, it is considered worthwhile to pursue even small improvements.

OBJECTIVE

The aim of this study was to test a novel smartphone app that leverages premium currency strategies developed by the mobile games industry in an attempt to improve engagement and retention with a smoking cessation intervention.

METHODS

We designed and developed a smoking cessation app called "Quittr" in line with previously developed smoking cessation mHealth apps. In addition to this established framework, we added a stand-alone fully featured city-building clicker-style game called "Tappy Town," and a premium virtual currency called "QuitCoins." The user earns QuitCoins for using the app in a way that contributes positively toward their quit attempt, and they can redeem these coins in Tappy Town for bonuses. To establish whether these features improved engagement and retention, we ran a 5-month randomized controlled trial where the intervention group had the full app with the extra games features, while the control group had the standard app only. Recruitment was performed via web-based advertising. Participants (N=175) had no direct contact with the researchers or other support staff.

RESULTS

No significant differences in terms of engagement, retention, or smoking outcomes were found between the control and intervention groups. However, survey data indicated that the majority of the participants valued Tappy Town (10/17, 59%) and the QuitCoins rewards system (13/17, 77%). Usage data also suggested that Tappy Town was widely played and was generally appealing to users (mean total time spent in app, control group: 797 seconds vs intervention group: 3502 seconds, P<.001). Analysis of the results suggests that users in the intervention group may have been negatively affected by the aspects of the chosen design, and some theories were explored to explain this unexpected outcome.

CONCLUSIONS

Although the novel features of the Quittr app failed to improve the key outcomes measured in this study, there were enough positive indications to warrant further exploration of the concept. Additional research will be required to identify and correct any design flaws that may have adversely affected our participants before a follow-up study can be completed.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Register ACTRN12617000491369; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=372661&isReview=true.

Using Serious Games for Antismoking Health Campaigns: Experimental Study

BACKGROUND

Serious games for health have been gaining in popularity among scholars and practitioners. However, there remain a few questions to be addressed.

OBJECTIVE

This study tests the effects of a serious game and fear appeals on smoking-related outcomes. More specifically, this research aims to understand how serious games function as a more effective vehicle for a health campaign than a traditional medium, such as a print-based pamphlet. Further, while serious games utilize a variety of persuasive strategies in the game's content, it is not clear whether fear appeals, which are widely used persuasive-message strategies for health, can be an effective strategy in serious games. Thus, we are testing the effect of fear appeals in a serious game.

METHODS

We created a computer game and a print brochure to educate participants about the risks of smoking. More specifically, a flash-based single-player game was developed in which players were asked to avoid cigarettes in the gameplay context. We also developed an online brochure based on existing smoking-related brochures at a university health center; antismoking messages on the computer game and in the brochure were comparable. Then, an experiment using a 2 (media type: game vs. print) x 2 (fearful image: fear vs. no-fear) between-subjects design was conducted. The study recruitment was announced to undergraduate students enrolled in a large, public Midwestern university in the United States. After a screening test, a total of 72 smokers, who reported smoking in the past 30 days, participated in the experiment.

RESULTS

Overall, gameplay, when compared to print-based pamphlets, had greater impacts on attitudes toward smoking and the intention to quit smoking. Further, the game's persuasive effects were especially pronounced when messages contained fear appeals. When fearful images were presented, participants in the game condition reported significantly more negative attitudes toward social smoking than those in the print condition [F(1,67)=7.28; P=.009; η_p2=0.10]. However, in the no-fear condition, there was no significant difference between the conditions [F(1,67)=0.25; P=.620]. Similarly, the intention to quit smoking [F(1,67)=4.64; P=.035; η_p2=0.07] and susceptibility [F(1,67)=6.92; P=.011; η_p2=0.09] were also significantly different between the conditions, but only when fear appeals were used.

CONCLUSIONS

This study extends fear appeal research by investigating the effects of different media types. It offers empirical evidence that a serious game can be an effective vehicle for fear appeals.

Evaluating Asthma Mobile Apps to Improve Asthma Self-Management: User Ratings and Sentiment Analysis of Publicly Available Apps

BACKGROUND

The development and use of mobile health (mHealth) apps for asthma management have risen dramatically over the past two decades. Asthma apps vary widely in their content and features; however, prior research has rarely examined preferences of users of publicly available apps.

OBJECTIVE

The goals of this study were to provide a descriptive overview of asthma mobile apps that are publicly available and to assess the usability of asthma apps currently available on the market to identify content and features of apps associated with positive and negative user ratings.

METHODS

Reviews were collected on June 23, 2020, and included publicly posted reviews until June 21, 2020. To characterize features associated with high or low app ratings, we first dichotomized the average user rating of the asthma app into 2 categories: a high average rating and a low average rating. Asthma apps with average ratings of 4 and above were categorized as having a high average rating. Asthma apps with average ratings of less than 4 were categorized as having a low average rating. For the sentiment analysis, we modeled both 2-word (bi-gram) and 3-word (tri-gram) phrases which commonly appeared across highly rated and lowly rated apps.

RESULTS

Of the 10 apps that met the inclusion criteria, a total of 373 reviews were examined across all apps. Among apps reviewed, 53.4% (199/373) received high ratings (average ratings of 4 or 5) and 47.2% (176/373) received low ratings (average ratings of 3 or less). The number of ratings across all apps ranged from 188 (AsthmaMD) to 10 (My Asthma App); 30% (3/10) of apps were available on both Android and iOS. From the sentiment analysis, key features of asthma management that were common among highly rated apps included the tracking of peak flow readings (n=48), asthma symptom monitoring (n=11), and action plans (n=10). Key features related to functionality that were common among highly rated apps included ease of use (n=5). Users most commonly reported loss of data (n=14) and crashing of app (n=12) as functionality issues among poorly rated asthma apps.

CONCLUSIONS

Our study results demonstrate that asthma app quality, maintenance, and updates vary widely across apps and platforms. These findings may call into question the long-term engagement with asthma apps, a crucial factor for determining their potential to improve asthma self-management and asthma clinical outcomes.

Playing Around with Quitting Smoking: A Randomized Pilot Trial of Mobile Games as a Craving Response Strategy

Objective: Strong cravings to smoke are an obstacle to cessation success. Unfortunately, cessation medication and counseling only modestly quell craving. This pilot study was designed to examine the feasibility of mobile games as a response strategy to craving and whether a fully powered trial is warranted. Materials and Methods: Smokers interested in quitting (N = 30) were offered 4 weeks of nicotine patch plus counseling and randomized to quit with (games-on) versus without (games-off) access to 11 commercial mobile games. Outcomes included post-target quit day (TQD) game play, craving, smoking, and quitting. Almost all P's were >0.05; outcomes should be interpreted with caution due to the small N. Results: Of games-on participants (n = 16), one played games ≥80% of days post-TQD (22/28 days); 38% played >1/3 of days; 25% did not play. Games-on participants reported games moderately helped them cope with cravings; M = 3.22 on a scale from 1 (not at all) to 5 (very much). Also, games-on participants showed a slight decrease in craving from baseline to 1-week post-TQD (2.35-2.25 on a 0-5 point-scale), whereas games-off participants showed an increase (2.01-2.53). Games-on participants showed greater decreases in craving after playing a game than after the passage of time (when an app imposed a 2-minute wait period following their game request), but there was little evidence games-on versus games-off participants differed in mean post-TQD cigarettes/day. Games-on participants reported modestly but not significantly higher continuous abstinence through day 28 (31.3% vs. 21.4%). Conclusion: Feasibility results encourage a fully powered trial of this easily disseminable intervention. Clinical Trial Registration: ClinicalTrials.gov NCT02164383.

Why Reviewing Apps Is Not Enough: Transparency for Trust (T4T) Principles of Responsible Health App Marketplaces

The overselling of health apps that may provide little benefit and even harm needs the health community’s immediate attention. With little formal regulation, a light-touch approach to consumer protection is now warranted to give customers a modicum of information to help them choose from the vast array of so-called health apps. We suggest 4 guiding principles that should be adopted to provide the consumer with information that can guide their choice at the point of download. We call these the Transparency for Trust (T4T) principles, which are derived from experimental studies, systematic reviews, and reports of patient concerns. The T4T principles are (1) privacy and data security, (2) development characteristics, (3) feasibility data, and (4) benefits. All our questions are in a simple form so that all consumers can understand them. We suggest that app stores should take responsibility for providing this information and store it with any app marketed as a health app. Even the absence of information would provide consumers with some understanding and fuel their choice. This would also provide some commercial impetus for app developers to consider this requested information from the outset.

Exploring Efficacy of a Serious Game (Tobbstop) for Smoking Cessation During Pregnancy: Randomized Controlled Trial

Background

Tobacco use during pregnancy entails a serious risk to the mother and harmful effects on the development of the child. Europe has the highest tobacco smoking prevalence (19.3%) compared with the 6.8% global mean. Between 20% to 30% of pregnant women used tobacco during pregnancy worldwide. These data emphasize the urgent need for community education and implementation of prevention strategies focused on the risks associated with tobacco use during pregnancy.

Objective

The aim of this study was to investigate the efficacy of an intervention that incorporates a serious game (Tobbstop) to help pregnant smokers quit smoking.

Methods

A two-arm randomized controlled trial enrolled 42 women who visited 2 primary care centers in Catalonia, Spain, between March 2015 and November 2016. All participants were pregnant smokers, above 18 years old, attending consultation with a midwife during the first trimester of pregnancy, and had expressed their desire to stop smoking. Participants were randomized to the intervention (n=21) or control group (n=21). The intervention group was instructed to install the game on their mobile phone or tablet and use it for 3 months. Until delivery, all the participants were assessed on their stage of smoking cessation during their follow-up midwife consultations. The primary outcome was continuous tobacco abstinence until delivery confirmed by the amount of carbon monoxide at each visit, measured with a carboxymeter.

Results

Continuous abstinence until delivery outcome was 57% (12/21) in the intervention group versus 14% (3/21) in the control group (hazard ratio=4.31; 95% CI 1.87-9.97; P=.001). The mean of total days without smoking until delivery was higher in the intervention group (mean 139.75, SD 21.76) compared with the control group (mean 33.28, SD 13.27; P<.001). In addition, a Kapplan-Meier survival analysis showed that intervention group has a higher abstinence rate compared with the control group (log-rank test, χ²₁=13.91; P<.001).

Conclusions

Serious game use is associated with an increased likelihood to maintain abstinence during the intervention period if compared with those not using the game. Pregnancy is an ideal opportunity to intervene and control tobacco use among future mothers. On the other hand, serious games are an emerging technology, growing in importance, which are shown to be a good tool to help quitting smoking during pregnancy and also to maintain this abstinent behavior. However, because of the study design limitations, these outcomes should be interpreted with caution. More research, using larger samples and longer follow-up periods, is needed to replicate the findings of this study.

Trial Registration

ClinicalTrials.gov NCT01734421; https://clinicaltrials.gov/ct2/show/NCT01734421 (Archived by WebCite at http://www.webcitation.org/75ISc59pB)