The Air Force Deployment Transition Center

Assessment of Program Structure, Process, and Outcomes

Terry L. Schell, Coreen Farris, Jeremy N. V. Miles, Jennifer Sloan, Deborah M. Scharf

RAND Health Quarterly, 2017; 7(1):7

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Abstract

It is often accepted as common knowledge that military personnel benefit from decompression time between a war zone and the home station. To capitalize on the potential benefits of a decompression period paired with support services, the U.S. Air Force established the Deployment Transition Center (DTC) at Ramstein Air Base in Germany in July 2010. The DTC provides airmen returning from combat missions with an opportunity to decompress and share lessons learned before returning to their home stations. The authors of this study evaluate the structure, processes, and outcomes of the DTC program. They find that, although a majority of participants found the DTC program worthwhile, a comparison of DTC participants and similar airmen who did not participate the program shows no evidence that the program helps reduce posttraumatic stress disorder symptoms, depressive symptoms, binge drinking, or social conflicts with family and coworkers. In addition, one of the DTC program elements appears to be similar to posttraumatic debriefing interventions, which several studies have found to be either ineffective or harmful. For these reasons, if the main goals of the DTC program are to improve behavioral health and social conflict outcomes, the authors recommend that the DTC program be discontinued or redesigned and Air Force resources invested in alternative programs. However, if the DTC program has other goals, such as providing rest and relaxation to airmen after a difficult deployment or capturing after-action information, then the authors recommend that these goals be documented and the DTC program be more specifically tailored to them.

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Following the Falklands War in 1982, United Kingdom military personnel returned from their deployments in one of two ways: entirely by sea or by a combination of sea and air travel. Those who returned entirely by sea had journeys that were one week longer than those who split their mode of travel. Press reports at the time suggested that those who spent longer getting home had better psychological outcomes than those who made the trip more quickly. Although outcome data to substantiate that claim have never surfaced, the narrative has entered into legend and is widely cited in support for providing decompression time between a war zone and home station.

Today, with the ubiquity of air travel, it is possible for service members to leave an active conflict zone and be greeted by their families within a matter of hours. Would these service members have better outcomes if they had more decompression time before returning to friends, families, and civilian settings? To capitalize on the potential benefits of a decompression period paired with support services, the U.S. Air Force established the Deployment Transition Center (DTC) at Ramstein Air Base in Germany in July 2010. The DTC provides airmen returning home from combat missions with an opportunity to decompress and share lessons learned before returning to their home stations. The program length is four days, during which service members receive an opportunity to debrief with fellow airmen and structured reintegration support during group sessions. During this time, DTC participants are encouraged to get adequate rest, and DTC staff handle such details as transportation arrangements to remove as many inconveniences and stressors as possible.

Ramstein Air Base serves as a "third location" (i.e., neither conflict zone nor home base), a neutral setting in which returning trauma-exposed airmen can focus on reintegration without the stressors of a conflict zone or the stimuli of civilian life, including the demands of family and friends. Ramstein was identified as a safe, peaceful setting in which to adjust slowly to and prepare for reintegration. The agricultural fields and mixed forests of southwestern Germany may feel more familiar to many Americans than the climate and geography of Iraq or Afghanistan, and the foreign location maintains a significant geographic separation from most family members and friends.

The DTC identified "decompression" as a theoretical construct that promotes a healthy psychological response to deployment trauma. According to program materials, decompression has three elements: (1) rest and relaxation (R&R), (2) debriefing adverse events experienced during the deployment, and (3) preparing for reintegration with family and friends by reviewing adaptive and maladaptive psychosocial coping strategies. Most elements of the DTC, from logistical support to its formal curriculum, are intended to contribute to one or more of these decompression elements. The DTC also focuses on collecting and sharing lessons learned during attendees' just-completed deployments. This is intended to help the Air Force identify policies and procedures that could improve mission effectiveness in theater. Airmen participate in group sessions led by a recently deployed Air Force facilitator in the same career field as the group. The information collected by the facilitator may be used to fine-tune the deployment process, training, or support of service members in the career field. Figure 1 shows the typical program schedule.

Figure 1. Schedule and Goals of DTC Groups and Activities

Schedule and Goals of DTC Groups and Activities

Attendance at the DTC is limited to airmen who were regularly exposed to significant risk of death in direct combat or regularly exposed to traumatic events during their deployment. At the time of this study, all members of four mission sets with high degrees of exposure to the risk of injury or death are preselected to attend: security forces, explosive ordinance disposal, tactical air control parties, and convoy operators. Other individuals or teams of airmen can be nominated by a deployed commander to attend the DTC if they experienced unanticipated or repeated exposure to trauma. DTC staff members estimate that approximately half of program participants are members of pre-identified mission sets, and half are command-nominated.

The goal of the DTC is to provide airmen with the skills necessary for successful psychosocial adjustment following their return to their home stations, workplaces, and families (e.g., adaptive coping mechanisms, knowledge of military mental health resources). However, in outward-facing materials, the program purposely avoids pointing to behavioral health outcomes as its primary goal. This ensures that DTC participants do not perceive the program as mental health treatment, which reduces stigma-related barriers to actively participating and benefiting from the program. Nonetheless, the outcomes selected for an internal Air Force evaluation, briefings on the program, and our communication with program leaders suggest that a reduction in post-deployment posttraumatic stress disorder (PTSD), depression symptoms, and alcohol misuse are important program targets. Relatedly, the DTC recruits a group of airmen who are at high risk for psychiatric disorders and includes in its curriculum structured program elements that were originally designed for the purpose of reducing psychiatric symptoms or psychological distress (Adler et al., 2009).

Evaluation Approach

The Defense Centers for Excellence in Psychological Health and Traumatic Brain Injury contracted with RAND to complete an evaluation of the DTC that would

  • document and evaluate the structure and processes of the DTC program
  • assess attendee satisfaction with the program
  • evaluate post-deployment outcomes.

Our approach to achieving these aims included (1) a site visit that included interviews with DTC leadership and staff, (2) a review of DTC program materials, (3) a literature review of interventions for individuals with trauma exposure, (4) review and summary of DTC-collected participant satisfaction data, and (5) an analysis of post-deployment outcomes as measured by the U.S. Department of Defense (DoD)-administered Post-Deployment Health Re-Assessment (PDHRA).

To document the structure and processes associated with the DTC, we visited the program site at Ramstein Air Base in Germany. While there, we toured the facilities and interviewed program leadership and staff members. To protect the privacy of airmen attending the program, we did not meet with attendees or observe groups. We used the information we gathered during the site visit and interviews, supplemented with information from the program concept of operations (U.S. Air Forces in Europe, 2014), to document the structure and processes of the program.

To review benefits associated with the DTC and lessons for similar programs across DoD, we reviewed the literature on programs and interventions for individuals who have experienced a traumatic event that sought to prevent the development of lasting mental health problems. We used this review to identify programs that are similar to the DTC and to summarize their evidence base. We first reviewed the small but growing literature on third-location decompression (TLD) programs, which most closely match the DTC's program structure. Second, we reviewed the small body of research on non-TLD programs aimed at armed forces personnel. The selected programs included either debriefing or psychoeducational strategies to reduce the likelihood of mental health problems post-deployment. These programs did not include an R&R component. Finally, we turned to the methodologically rigorous body of work on PTSD prevention among civilians exposed to traumatic events. Although lessons from such programs may not be perfectly aligned with programs serving military populations, their outcomes provided a starting point for evaluation and helped to guide expectations regarding the DTC's outcomes.

We supplemented our literature review with a review of program participants' responses to an anonymous satisfaction survey administered to airmen at the end of their DTC stay. This survey was designed and administered by DTC program staff. The survey contained four sections. The first queried attendees' opinions of the DTC overall, specific program content, and perceived skills and readiness to reintegrate with family and friends. The second section assessed respondents' current well-being, including perceived physical fitness, psychological well-being, and work-related quality of life. The third section included two questions about religious services, and the final section of the survey used open-ended questions to assess what each participant (1) liked about the DTC, (2) disliked about the DTC, and (3) would change about the DTC.

Finally, we assessed the difference between DTC attendees and a comparison group of similar airmen who did not attend the DTC. All outcomes were assessed using data available on the DoD-administered PDHRA questionnaire, given three to six months after return from deployment. We identified four measures on this assessment that map to some of the primary DTC program goals: PTSD symptoms, depressive symptoms, binge drinking, and social conflicts with family and coworkers. Using individual participant identifiers and attendance dates for DTC attendees, we compared DTC attendees with a matched control group on the four available and relevant outcomes. Matching was done on the basis of airman and deployment characteristics that were assessed on the Post-Deployment Health Assessment (PDHA), a mandatory survey given within 30 days of the end of the deployment.

Key Findings

Lessons from Similar Programs

Our review of TLD program evaluations identified no high-quality randomized controlled trials, but there are published studies on program implementation and participant satisfaction. These studies revealed high levels of participant satisfaction with TLD programs. We also identified a prior study of the DTC itself, which indicated that fewer DTC participants reported at least one PTSD symptom following a deployment (14.1 percent) compared with nonparticipants (23.4 percent; Wirick, Garb, and Dickey, 2012). According to this study, airmen who attended the DTC were also less likely to screen positive for alcohol misuse at follow-up than airmen who did not attend.

Components of TLD programs can be implemented without requiring a third location. That is, service members may participate in debriefing sessions or receive psychoeducation about mental health symptoms and family reintegration on return to their home station instead of at a third location. The documented outcomes of these practices are mixed (Mulligan, Fear, et al., 2011), with some programs demonstrating positive outcomes for those with high combat exposure (Adler et al., 2009), and others failing to show a positive impact associated with the program (e.g., Deahl et al., 1994).

We highlight one particular evaluation of a reintegration program for its direct relevance to the DTC. Adler and colleagues (2009) conducted a randomized controlled trial of Battlemind, a debriefing program—delivered at a home station—that provides an opportunity to reflect on deployment experiences and discuss the transition from combat to home. The DTC uses revised training materials from this program for its Combat Bridge session. The evaluation showed that soldiers who attended Battlemind had fewer PTSD, depression, and sleep symptoms four months after the intervention than those who did not attend, but these reductions were true only among those who had high levels of combat exposure (Adler et al., 2009). Moreover, the size of this effect, even among those with high combat exposure, was small. For example, soldiers who received the Battlemind debriefing scored three points lower on the PTSD Checklist (Weathers et al., 1993), a drop that is not considered to be a clinically significant change (Monson et al., 2008; National Center for PTSD, 2012).

In addition to evaluations of military-specific reintegration programs, it also possible to glean insight from civilian programs designed to prevent the development of mental health problems following exposure to a trauma. We reviewed the outcomes of PTSD prevention programs that share commonalities with the DTC.

Psychological debriefing is a group-based intervention in which survivors of a shared trauma describe and relive the trauma in detail with the expectation that emotional catharsis or ventilation will prevent development of more severe trauma symptomatology. A systematic review of the extensive literature on posttraumatic debriefing concluded that individuals exposed to psychological debriefing programs are just as likely to develop PTSD as individuals who do not participate (Rose et al., 2002). In fact, two rigorous evaluations found that debriefing was associated with an increased risk of PTSD (Bisson et al., 1997; Hobbs et al., 1996). At this date, researchers and clinical practice guidelines recommend that civilian-style debriefing programs not be offered to trauma survivors (U.S. Department of Veterans Affairs and U.S. Department of Defense, 2010; McNally, Bryant, and Ehlers, 2003; Nash and Watson, 2011; Rose et al., 2002). Because the DTC includes program elements that are similar to those used in critical incident stress debriefing, it is likely that those particular elements are contraindicated by existing DoD and U.S. Department of Veterans Affairs treatment guidelines.

An alternative to providing prevention services to all trauma-exposed individuals is to provide services only to those who have begun to develop traumatic stress symptoms (but who have not yet developed PTSD). The best-studied and most widely disseminated intervention for early trauma symptoms is trauma-focused cognitive behavioral therapy (TF-CBT), a brief, four- to five-session therapy that includes education about stress responses to trauma, habituation to the trauma memory, real-world exposures to safe but avoided situations, and cognitive therapy to modify maladaptive beliefs associated with the trauma (U.S. Department of Veterans Affairs and U.S. Department of Defense, 2010; McNally, Bryant, and Ehlers, 2003). Trauma-exposed individuals who have posttraumatic psychological symptoms and who receive TF-CBT are less likely to develop PTSD (Roberts et al., 2009).

Lessons from Participant Experiences

Airmen who attended the DTC were invited on the last day of the program to complete a satisfaction survey. The survey was designed and administered by DTC staff. The DTC shared with the RAND research team aggregate survey results from 1,552 DTC attendees. Given that the data were shared in de-identified and aggregate form, we are unable to describe associations between attendee characteristics (gender, rank, or deployment experience) and satisfaction with the program. Nonetheless, the survey data provide a general picture of airmen's experiences at the DTC and their general subjective states as they prepared to return home.

Eighty percent of attendees reported that the DTC was a worthwhile experience, and three-quarters indicated that it helped prepare them to return home. In open-field portions of the survey, attendees reported that they liked the DTC accommodations, particularly the rooms in which they stayed, noting that the generous accommodations contributed to the perceived effectiveness of the DTC. Among those offering comments on the DTC's location, views were mixed. About half commented positively (49 percent) about being in Germany, but 31 percent had negative opinions about the distance between their living quarters and other buildings on the base, such as restaurants or the gym.

In general, respondents rated the DTC's classroom modules highly, with approximately two-thirds or more agreeing that each program module was helpful and increased reintegration knowledge and skills. Similarly, the majority indicated that the length of the program was "just right."

The survey also asked DTC attendees to describe their current well-being, including perceived physical health, emotional well-being, and work-related quality of life. In general, respondents indicated that their well-being and work-related quality of life were good and that the DTC had facilitated their ability to relax. More than 90 percent of participating airmen believed they had the skills to return home, and 87 percent said that they were emotionally prepared to reintegrate.

Negative comments were generally in the areas of transportation, program rules (such as alcohol limits and curfews), and mandatory attendance at the DTC. There were numerous suggestions to improve the shuttle system. There were also suggestions to revisit the protocol for selecting DTC attendees, including making attendance optional or taking into consideration whether an airman saw combat during the deployment. Other suggestions included making the field trip outside Ramstein optional and improving communication leading up to DTC stays, such as what to expect and what to bring.

Lessons from Quantitative Assessment of Program Outcomes

To evaluate the outcomes associated with DTC attendance, we conducted a propensity score analysis to estimate the effect of program attendance on PTSD symptoms, depressive symptoms, alcohol use, and family/work conflict following a deployment. The gold standard in evaluating an intervention is the randomized controlled trial, in which individuals who are eligible for a program are randomly assigned to either the intervention or control group. However, all eligible airmen who were able to attend the program did so, precluding a traditional randomized controlled trial. The propensity score analysis attempts to achieve the type of balance between comparison groups that is achieved with random assignment even when random assignment is not possible. We used propensity score–based analyses to compare DTC attendees with a group of similar airmen who did not attend the DTC. All background variables used for propensity matching were taken from the mandatory PDHA administered within 30 days of redeployment (i.e., return from deployment), including demographic factors, career field, deployment characteristics (e.g., length, combat exposure), physical injuries, and deployment trauma. We compared DTC attendees with the matched control group on four outcomes measured in the PDHRA administered 90–180 days after DTC attendance: PTSD symptoms, depressive symptoms, alcohol use, and conflicts with family and coworkers.

We controlled for demographic differences between groups using propensity weights to the extent possible, but some differences remained significant and may have posed a threat to the validity of the study. To avoid biases caused by these imbalances, we estimated treatment effects while including statistical covariates (i.e., doubly robust estimates). Specifically, we included as covariates variables that were significantly different across groups even after propensity weighting. We also included covariates when that variable was a strong predictor of our outcomes of interest.

The differences in key outcomes between DTC participants and their historical controls (i.e., matched airmen who completed their deployments before the DTC was available and, therefore, did not attend) were small and not statistically significant for PTSD symptom counts, frequency of depressive symptoms, and incidence of social conflict. For binge drinking, the mean for the DTC attendees was approximately 25 percent lower than that for the control group. To assess historical trends, we examined these outcomes over time among airmen who were not sent to the DTC and were not in the control group. There were no significant trends in PTSD, depression, or social conflict observed in the airmen who did not attend the DTC over this period. However, there was a significant reduction in post-deployment binge drinking observed over this time period even for those airmen who did not attend the DTC. This historical trend toward less alcohol use across the entire Air Force fully accounted for the observed difference in alcohol use when comparing DTC attendees to their historical controls (i.e., the DTC added no beneficial effect over and above the changes seen across the service over the same period).

Overall, we found no evidence of significant psychological or behavioral health effects attributable to the DTC among airmen who attended the program. Because we used a large sample and doubly robust methods to estimate the treatment effect, the effects were estimated with high precision. The findings rule out with relatively high confidence clinically meaningful improvement in mental health symptoms caused by the DTC. In contrast, while the study did not find a statistically significant causal effect of DTC attendance on binge drinking (even at a relaxed criteria of p < 0.10), the confidence intervals on the effect did not rule out the possibility of a clinically meaningful benefit.

Recommendations

The primary findings from this evaluation are that (1) one of the DTC program elements, as implemented, appears to be similar to posttraumatic debriefing interventions, which have been found to be either ineffective or harmful across several studies and are contraindicated by DoD, U.S. Department of Veterans Affairs, and World Health Organization clinical practice guidelines; (2) most program attendees believe that attending the DTC was a worthwhile experience that helped prepared them for reintegration; but (3) we did not observe benefits of DTC attendance on behavioral health or social conflict outcomes when attendees were compared with a matched group of airmen who did not attend the DTC. These findings are tempered by the limitations of the research design and available data. In particular, the studies that have evaluated posttraumatic debriefing interventions have been conducted primarily following noncombat trauma exposure in civilian populations. In addition, the findings of the quantitative assessment of the DTC are limited to the handful of measures that are available on the PDHRA assessment, which may not capture the full range of potential DTC outcomes.

Our recommendations depend largely on whether the outcomes included in this quantitative evaluation are deemed a good or poor match for the program's goals. If program administrators and Air Force decisionmakers view reductions in post-deployment PTSD symptoms, depression symptoms, binge drinking, and social conflict as constituting the core of the DTC's mission, then we would recommend that the resources directed to the DTC be invested in alternative programs or treatments that have been demonstrated to improve those outcomes. Specifically, we would recommend that the Air Force:

  • Discontinue the DTC in its current form, and do not recreate the DTC for future conflicts using the existing procedures and programming; this program did not significantly reduce PTSD symptoms, depression symptoms, binge drinking, or social conflict following trauma exposure.
  • Instead, invest resources in programs that have been demonstrated to reduce post-deployment PTSD symptoms, depression symptoms, binge drinking, or social conflict; or invest those resources into new, promising programs that the Air Force evaluates for beneficial effects.

On the other hand, if program administrators and Air Force decisionmakers decide that the outcomes assessed in this study are not the primary program goals, then our recommendations are quite different. For example, if the DTC is justified on the basis of goals related to R&R for airmen, or the collection of after-action information, the DTC may be a valuable program for the Air Force even in the absence of effects on behavioral health. In that case, we suggest that the Air Force:

  • Revisit, document, and evaluate selected DTC program goals.
    • Develop a revised concept of operations that identifies how the program design, staffing, eligibility, and location are structured to achieve the goals that have been identified. For example, if R&R are key goals, the program materials should explain how the design, staffing, eligibility, and facilities relate to that goal. This may suggest changes to the DTC program.
    • Consider removing curriculum elements that have unsuccessfully targeted mental health goals, if such goals are not the primary focus of the program.
    • Develop an evaluation plan to empirically assess the effect of DTC attendance on important program objectives.
  • Even if improving behavioral health is identified as a key program goal, remove the contraindicated program element of group processing of psychological trauma, and develop policy to prevent its reintroduction.

During our visit to the DTC, it was clear that the program staff were enthusiastic and committed to their mission. Participating airmen consistently noted the quality of the staff and the skill with which they approached their mission on satisfaction surveys. Unfortunately, many well-intended and well-liked programs prove to be ineffective. In many ways, the history of mental health prevention efforts could be summarized in the same way. It has proved extraordinarily challenging to reach the right people, at the right time, and with the right intervention to prevent the negative consequences of trauma exposure. In light of these challenges, it is not surprising that few prevention programs have been found to have benefits on post-deployment PTSD, depression, binge drinking, and social conflict. However, these evaluations are key for promoting ongoing program modification or program development that can improve outcomes for those airmen who serve their country on difficult or dangerous deployments.

This research was sponsored by the Defense Centers of Excellence for Psychological Health and Traumatic Brain Injury (DCoE) and conducted within the Forces and Resources Policy Center of the RAND National Defense Research Institute, a federally funded research and development center sponsored by the Office of the Secretary of Defense, the Joint Staff, the Unified Combatant Commands, the Navy, the Marine Corps, the defense agencies, and the defense Intelligence Community.

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References

Adler, A. B., P. D. Bliese, D. Mcgurk, C. W. Hoge, and C. A. Castro, "Battlemind Debriefing and Battlemind Training as Early Interventions with Soldiers Returning from Iraq: Randomization by Platoon," Journal of Consulting and Clinical Psychology, Vol. 77, No. 5, 2009, pp. 928–940.

Bisson, J. I., P. Jenkins, J. Alexander, and C. Bannister, "Randomised Controlled Trial of Psychological Debriefing for Victims of Acute Burn Trauma," British Journal of Psychiatry, Vol. 171, 1997, pp. 78–81.

Deahl, M. P., A. B. Gillham, J. Thomas, M. M. Searle, and M. Srinivasan, "Psychological Sequelae Following the Gulf War. Factors Associated with Subsequent Morbidity and the Effectiveness of Psychological Debriefing," British Journal of Psychiatry, Vol. 165, No. 1, 1994, pp. 60–65.

Hobbs, M., R. Mayou, B. Harrison, and P. Worlock, "A Randomised Controlled Trial of Psychological Debriefing for Victims of Road Traffic Accidents," British Medical Journal, Vol. 313, 1996, pp. 1438–1439.

McNally, R. J., R. A. Bryant, and A. Ehlers, "Does Early Psychological Intervention Promote Recovery from Posttraumatic Stress?" Psychological Science in the Public Interest, Vol. 4, No. 2, 2003, pp. 45–79.

Monson, C. M., J. L. Gradus, Y. Young-Xu, P. P. Schnurr, J. L. Price, and J. A. Schumm, "Change in Posttraumatic Stress Disorder Symptoms: Do Clinicians and Patients Agree?" Psychological Assessment, Vol. 20, No. 2, 2008, pp. 131–138.

Mulligan, K., N. T. Fear, N. Jones, S. Wessely, and N. Greenberg, "Psycho-Educational Interventions Designed to Prevent Deployment-Related Psychological Ill-Health in Armed Forces Personnel: A Review," Psychological Medicine, Vol. 41, No. 4, 2011.

Nash, W. P., and P. J. Watson, "Review of VA/DoD Clinical Practice Guideline on Management of Acute Stress and Interventions to Prevent Posttraumatic Stress Disorder," Journal of Rehabilitation Research and Development, Vol. 49, No. 5, 2011, pp. 637–648.

Roberts, N. P., N. J. Kitchiner, J. Kenardy, and J. Bisson, "Multiple Session Early Psychological interventions for the Prevention of Post-Traumatic Stress Disorder," Cochrane Database of Systematic Reviews, Vol. 3, 2009.

Rose, S., J. Bisson, R. Churchill, and S. Wessely, "Psychological Debriefing for Preventing Post Traumatic Stress Disorder (PTSD)," other, Cochrane Database of Systematic Reviews, No. 2, 2002.

U.S. Air Forces in Europe, other, Concept of Operations: Deployment Transition Center [amendment to tmt haf1310014987], February 2014. As of April 22, 2016:
http://www.ramstein.af.mil/shared/media/document/AFD-141016-012.pdf

U.S. Department of Veterans Affairs and U.S. Department of Defense, other, VA/DoD Clinical Practice Guideline for Management of Post-Traumatic Stress, 2010. As of April 18, 2016:
http://www.healthquality.va.gov/guidelines/MH/ptsd/cpg_PTSD-full-201011612.PDF

Weathers, F. W., B. T. Litz, D. S. Herman, J. A. Husk, and T. M. Keane, "The PTSD Checklist (pcl): Reliability, Validity, and Diagnostic Utility," Annual Convention of the International Society for Traumatic Stress Studies, International Society for Traumatic Stress Studies, 1993.

Wirick, Aaron, Howard Garb, and David Dickey, "Report on the Deployment Transition Center: Post-Deployment Outcomes," other, unpublished manuscript, 2012.

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