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The purpose of this study was to develop a safe and effective method of inserting one tuberosity screw and to determine whether retro-tubercular (RT)-Open-wedge high tibial osteotomy (OWHTO) with tuberosity screw fixation can be conducted to overcome the problem of osteotomized tubercle and produce favorable outcomes compared to RT-OWHTO without tuberosity screw fixation.From 2018 to 2020, patients who underwent bi-planar RT-OWHTO were allocated as two groups (RT-OWHTO without tuberosity screw fixation as group I and with screw fixation as group II). Computed tomography (CT) was used to analyze osteotomy configurations such as RT gap and tip distance, and union of the main and second plane osteotomy sites. The RT gap distance was measured as the length of the osteotomy gap. The RT tip distance was measured as the length of the gap at the tip of the tibial tubercle. Post-operative complications were analyzed also. To evaluate the neurovascular (NV) approximity of screw fixation group, the pre-operative magnetic resonance imaging (MRI) images were referenced on the post-operative CT for the assessment of the safe zone.In total, 44 knees in group I and 46 knees in group II were enrolled. The RT gap distance (2.58 ± 0.69 mm vs. 0.57 ± 0.57 mm; p .001) and RT tip distance (4.31 ± 1.60 mm vs. 1.48 ± 1.42 mm; p .001) were significantly larger in group I than in group II. The sum of union grade in the second plane osteotomy site (17.93 ± 2.18 points vs. 22.24 ± 2.57 points; p .001) was statistically different between two groups at three months post operatively. Post-operative tuberosity prominence occurred in five knees only in group I (p = 0.025), although tibial tuberosity fracture developed in seven cases in group II compared with two cases in group I with no statistical significance. NV was safe when the screw was inserted medially.RT-OWTHO with one-screw fixation for the tuberosity was effective in terms of tuberosity prominence and the union of the second plane osteotomy site. However, it also produced another problem, such as tuberosity fracture. In addition, a tuberosity screw was safe when it was inserted in the medial-distal direction.Cohort study; level III.

This study aimed to evaluate the permissible joint-line obliquity (JLO) based on radiologic and clinical outcomes with midterm follow-up after medial open-wedge high tibial osteotomy (MOWHTO).Patients who had undergone MOWHTO from March 2014 to May 2016 were retrospectively evaluated. They were divided into 4 groups based on JLO as represented by postoperative medial proximal tibial angle (MPTA). Radiologic parameters including MPTA, joint-line orientation angle (JLOA), joint-line convergence angle (JLCA), posterior tibial slope, weightbearing line ratio (WBLR), and coronal translation were analyzed. Clinical outcomes were evaluated with American Knee Society Score (AKSS), Western Ontario and McMaster University Index, and short-form 36 health survey (SF-36). The changes between preoperation and final follow-up in JLOA and MPTA were defined as ΔJLOA and ΔMPTA.A total of 135 knees were finally included (MPTA ≤90.32° as group I; 90.33° to 92.62° as group II; 92.74° to 95.22° as group III; and ≥95.23° as group IV). The last follow-up MPTA, JLOA, and JLCA values were different between the groups (P.001, P.001, and P = .015, respectively). WBLR and JLOA positively correlated with MPTA; however, WBLR showed an abrupt increase at MPTA96.5°, and the JLOA distribution tended to be greater than the regression line at MPTA96°. Moreover, ΔJLOA was not as large as ΔMPTA. The percentage of patients attaining a minimal clinically important difference was significantly lower in the AKSS-functional score and SF-36 physical component summary in group IV (P = .008 and 0.021, respectively).The JLOA did not change as much as the MPTA, but an MPTA95.2° abruptly increased the JLOA and valgus overcorrection after MOWHTO. Poor clinical outcomes were more evident in excessive MPTA (95.2°) than in mildly undercorrected or properly corrected MPTA (95.2°).III, retrospective cohort study.

The purpose of this study was to verify the efficacy of a novel technique for additional tying on the adjustable-loop device to prevent stress concentration on the graft loop end and gradual loop lengthening.A total of 124 patients who underwent anterior cruciate ligament reconstruction using hamstring autografts from 2014 to 2017 were included in this retrospective study. After 1:1 propensity score matching, two groups were formed (group I: 50 patients without tying vs. group II: 50 patients with tying). Anterior laxity was evaluated using side-to-side differences. Tunnel length, loop length, and graft-tunnel gap were measured using follow-up magnetic resonance imaging. The signal-to-noise ratio was calculated at the loop end, loop inner side, tunnel entrance, and graft mid-substance. The clinical outcomes were assessed using the International Knee Documentation Committee score, Lysholm score, pivot shift test, and Lachman test.The average follow-up period was 63.2 ± 4.8 and 53.8 ± 11.9 months in groups I and II, respectively. Anterior laxity showed that side-to-side differences improved significantly 6 months postoperatively in both the groups. Although the anterior laxity improved in group II (2.9 ± 1.0 to 1.6 ± 0.8, p 0.001), it deteriorated in group I (2.5 ± 1.5 to 3.3 ± 1.3 mm, p 0.001) at the final follow-up. The graft-tunnel gap was significantly larger in group I (p 0.001). The signal-to-noise ratios of the loop end and loop inner side were significantly higher in group I (p 0.001 and p = 0.020, respectively). The clinical outcomes at the final follow-up were not significantly different between the groups.The additional tying on the adjustable-loop device was not superior to the control group in clinical stability examination or outcome. However, it was effective in anterior laxity measured by stress radiographs, preventing stress on the adjustable-loop device, and gradual graft loop lengthening.Level III.

Several methods have been developed to prevent lateral hinge fractures (LHFs), using only classic statistical models. Machine learning is under the spotlight because of its ability to analyze various weights and model nonlinear relationships. The purpose of this study was to create a machine learning model that predicts LHF with high predictive performance.Data were collected from a total of 439 knees with medial osteoarthritis (OA) treated with Medial open wedge high tibial osteotomy (MOW-HTO) from March 2014 to February 2020. The patient data included age, sex, height, and weight. Preoperative, determined, and modifiable factors were categorized using X-ray and CT data to create ensemble models with better predictive performance. Among the 57 ensemble models, which is the total number of possible combinations with six models, the model with the highest area under curve (AUC) or F1-score was selected as the final ensemble model. Gain feature importance analysis and the Shapley additive explanations (SHAP) feature explanation were performed on the best models.The ensemble model with the highest AUC was a combination of a light gradient boosting machine (LGBM) and multilayer perceptron (MLP) (AUC = 0.992). The ensemble model with the highest F1-score was the model that combined logistic regression (LR) and MLP (F1-score = 0.765). Distance X was the most predictive feature in the results of both model interpretation analyses.Two types of ensemble models, LGBM with MLP and LR with MLP, were developed as machine learning models to predict LHF with high predictive performance. Using these models, surgeons can identify important features to prevent LHF and establish strategies by adjusting modifiable factors.Retrospective cohort study.

Background: The maximum standardized uptake value (SUVmax), as determined on combined single-photon emission computed tomography and conventional computed tomography (SPECT/CT), can be an indicator of biomechanical changes due to the load redistribution effect after medial open-wedge high tibial osteotomy (MOW-HTO). Purpose/Hypothesis: The purposes of this study were to (1) analyze serial changes in the SUVmax in the medial, lateral, and patellofemoral compartments after MOW-HTO and (2) identify the contributing factors that affect changes in the SUVmax. The hypotheses were that (1) an elevated SUVmax in the medial compartment would be transferred to the lateral compartment because of the load redistribution effect and (2) there would be contributing factors that cause SUVmax changes. Study Design: Case series; Level of evidence, 4. Methods: Included were 67 knees that were treated with biplanar MOW-HTO between March 2019 and December 2020. SPECT/CT was performed immediately after surgery and at 3 months and 1 year postoperatively to determine the serial load redistribution effect of MOW-HTO. The Pearson correlation coefficient was used to evaluate the relationship between SUVmax and radiological parameters, and subgroup analyses were conducted to compare the SUVmax according to associated cartilage procedures and the weightbearing line ratio (WBLR). Results: The SUVmax in the medial and lateral compartments increased at 3 months but decreased at 1 year postoperatively. The load redistribution effect was most prominent in the anterior zones of the femur (medial: P = .041; lateral: P = .012). In the patella, the SUVmax decreased in both the medial and the lateral zones at all follow-up times ( P < .001 for all). The SUVmax in the anterolateral and posterolateral articular zones of the femur increased with a greater preoperative WBLR ( r = 0.256, P = .039; and r = 0.261, P = .036, respectively). Patients who underwent an associated cartilage procedure had a significantly higher SUVmax in the anteromedial and posteromedial articular zones of both the femur and the tibia at 1 year postoperatively ( P ≤ .002 for all). Conclusion: After MOW-HTO, the unloading effect in the anteromedial articular zone of the femur was the most significant. A greater SUVmax in the lateral zones of the femur was observed in cases of overcorrection. The SUVmax in the medial zones was higher postoperatively in patients with associated cartilage procedures.

Appropriate prediction models can assist healthcare systems in delaying or reversing osteoarthritis (OA) progression. We aimed to identify a reliable algorithm for predicting the progression rate and fate of OA based on patient-specific information. From May 2003 to 2019, 83,280 knees were collected. Age, sex, body mass index, bone mineral density, physical demands for occupation, comorbidities, and initial Kellgren-Lawrence (K-L) grade were used as variables for the prediction models. The prediction targets were divided into dichotomous groups for even distribution. We compared the performances of logistic regression (LR), random forest (RF), and extreme gradient boost (XGB) algorithms. Each algorithm had the best precision when the model used all variables. XGB showed the best results in accuracy, recall, F1 score, specificity, and error rates (progression rate/fate of OA: 0.710/0.877, 0.542/0.637, 0.637/0.758, 0.859/0.981, and 0.290/0.123, respectively). The feature importance of RF and XGB had the same order up to the top six for each prediction target. Age and initial K-L grade had the highest feature importance in RF and XGB for the progression rate and fate of OA, respectively. The XGB and RF machine learning algorithms showed better performance than conventional LR in predicting the progression rate and fate of OA. The best performance was obtained when all variables were combined using the XGB algorithm. For each algorithm, the initial K-L grade and physical demand for occupation were the greatest contributors with superior feature importance compared with the others.

Background:Neurovascular injury is a serious complication after opening-wedge high tibial osteotomy (OWHTO).Purpose:To evaluate (1) how neurovascular injuries during fixation can be prevented and (2) whether a lateral hinge–directed posteromedial fixation system provides comparable neurovascular safety during OWHTO to conventional and custom-made locking plate systems.Study Design:Cohort study; Level of evidence, 3.Methods:Included were 275 knees that underwent OWHTO from March 2014 to May 2018. The knees were divided into 4 groups based on the type of fixation system used: (1) lateral hinge–directed system (LCfit HTO; LCfit group), (2) TDM decisive wedge locking plate (TDM group), (3) OhtoFix anatomic locking metal block plate (OhtoFix group), and (4) TomoFix titanium locking plate (TomoFix group). Using postoperative computed tomography, the following variables among the groups were compared: screw insertion angle relative to the tibia posterior cortex in the axial plane, length, proximity to neurovascular structures, and safety angle of screw fixation (angle between the most proximal posterior screw insertion line and a line tangent to the popliteal artery from the screw hole). Radiological and clinical outcomes were also compared between groups.Results:The screw angle was significantly smaller and the distance from neurovascular structures to the screw extension line was significantly farther in the LCfit group compared with the other 3 groups ( P < .001 for both). The safety angle was also wider in the LCfit group than in the other groups ( P < .001). There were no significant differences in radiologic or clinical outcomes between the groups during follow-up.Conclusion:The distance from the neurovascular structures to the screw extension line was significantly farther, and the safety angle was also significantly wider with the laterally directed posteromedial plate system compared with the other systems. There were no neurovascular injuries in any group or significant differences in clinical outcomes or radiological parameters between the LCfit and the other locking plate systems.

Factors affecting the progression rate and fate of osteoarthritis need to be analyzed when considering patient-specific situation. This study aimed to identify the rate of remarkable progression and fate of primary knee osteoarthritis based on patient-specific situations. Between May 2003 and May 2019, 83,280 patients with knee pain were recruited for this study from the clinical data warehouse. Finally, 2492 knees with pain that were followed up for more than one year were analyzed. For analyzing affecting factors, patient-specific information was categorized and classified as demographic, radiologic, social, comorbidity disorders, and surgical intervention data. The degree of contribution of factors to the progression rate and the fate of osteoarthritis was analyzed. Bone mineral density (BMD), Kellgren–Lawrence (K–L) grade, and physical occupational demands were major contributors to the progression rate of osteoarthritis. Hypertension, initial K–L grade, and physical occupational demands were major contributors to the outcome of osteoarthritis. The progression rate and fate of osteoarthritis were mostly affected by the initial K–L grade and physical occupational demands. Patients who underwent surgical intervention for less than five years had the highest proportion of initial K–L grade 2 (49.0%) and occupations with high physical demand (41.3%). In identifying several contributing factors, the initial K–L grade and physical occupational demands were the most important factors. BMD and hypertension were also major contributors to the progression and fate of osteoarthritis, and the degree of contribution was lower compared to the two major factors.

The purpose of this study was to compare the outcomes of middle-aged patients with anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) insufficiency by assessing different groups: high tibial osteotomy (HTO), HTO with combined ligament reconstruction, and isolated ligament reconstruction according to the alignment change and medial compartment osteoarthritis (OA).From 2014 to 2019, middle-aged (40-65 years) patients with knee instability were enrolled in this retrospective study. They were categorized into three groups: group I, HTO; group II, HTO with combined ACL or PCL reconstruction; and group III, isolated ligament reconstruction. Radiological outcomes, including Kellgren-Lawrence grade, mechanical femorotibial angle (mFTA), weight-bearing line (WBL) ratio, and posterior tibial slope were compared. Knee stability and clinical outcomes were also compared.Seventy-nine patients completed the final assessment. Group I was older than other two groups (p = 0.006). Groups I and II had a higher body mass index (p = 0.043) and more preoperative varus alignment than group III (p 0.001). OA severity was ranked in the order of group I, II, and III (p 0.001). Group I showed more valgus alignment than group II after HTO (p = 0.024 for mFTA and 0.044 for WBL ratio, respectively). Compared to their preoperative status, all three groups showed significant improvement in knee stability (p 0.001); however, group I showed inferior knee stability regardless of ACL or PCL reconstruction (p 0.001 and 0.043, respectively). All clinical scores significantly improved in the three groups (p 0.001), and they showed comparable clinical outcomes in the final assessment.Our strategy in managing middle-aged patients with knee instability according to the varus alignment and medial degeneration showed favorable stability and clinical outcomes. Middle-aged patients with knee instability should be managed with different strategies depending on their status.Case-control study; Level-III.

Background: Corrective osteotomy around the knee is based on deformity profiles of the femoral and tibial sides. Opening-wedge high tibial osteotomy (OWHTO) can be favored if the outcomes are not different, even if there is a certain degree of abnormal parameters after correction. Purpose/Hypothesis: The purpose of this study was to identify the factors associated with unfavorable radiological outcomes after OWHTO for varus knees. Our hypothesis was that there would be an optimal situation in which double-level osteotomy (DLO) has advantages over isolated OWHTO and an optimal cutoff value of structural parameters for which DLO should be considered in patients with severe varus knees. Study Design: Case-control study; Level of evidence, 3. Methods: The radiological and clinical outcomes of 337 patients who underwent OWHTO were retrospectively evaluated. A subgroup analysis was performed according to the weightbearing line ratio (WBLR) (group 1: 75th percentile) and factors associated with unfavorable radiological outcomes. For the assessment of cutoff values of the parameters favoring DLO, unfavorable radiological outcomes were categorized as follows: (1) medial proximal tibial angle (MPTA) >95°, (2) joint-line convergence angle (JLCA) >4° (insufficient medial release), (3) JLCA Results: The mean follow-up period was 66.2 ± 19.1 months. A low preoperative WBLR was related to a larger preoperative to postoperative change (Δ) in the WBLR, a larger reduction in coronal translation, a larger ΔMPTA, a wide preoperative lateral joint space, and a narrow preoperative medial joint space ( P < .001, P < .001, P < .001, P = .016, and P = .003, respectively). However, only an MPTA >95° was significantly related to a low WBLR in the subgroup analysis according to unfavorable radiological outcomes ( P = .038). The cutoff value of ΔWBLR causing an MPTA >95° was 46.5%, which showed a good area under the curve of 0.800, with a sensitivity of 74.4% and a specificity of 82.7%. The clinical outcomes significantly improved at the final follow-up compared with those preoperatively, with no significant differences between the WBLR groups. Conclusion: A ΔWBLR ≥46.5% led to an MPTA >95°. However, clinical outcomes were not affected. DLO should be considered if the surgeon desires a postoperative MPTA ≤95°.

Background: Proper anatomic restoration is an important consideration for meniscal allograft transplantation (MAT), even with the different anatomica characteristics between the medial meniscus and lateral meniscus. Purpose/Hypothesis: The purpose of this study was to assess the accuracy of anatomic restoration in medial and lateral MAT (MMAT and LMAT) procedures and to compare their outcomes. We hypothesized that (1) the anatomic differences between the medial and lateral menisci will mean a less accurate anatomic restoration for MMAT and (2) clinical outcomes after MMAT will be inferior compared with LMAT. Study Design: Cohort study; Level of evidence, 3. Methods: We retrospectively evaluated 20 patients who underwent MMAT using the bone plug technique and 21 patients who underwent LMAT using the keyhole technique at a single institution from July 2014 to June 2019. Demographic data, previous surgeries, and concomitant procedures were recorded, as were lower limb alignment and osteoarthritis grade on radiographs. Using preoperative and follow-up magnetic resonance imaging, the meniscal position, rotation, extrusion, and intrameniscal signal intensity were evaluated. Clinical outcomes were evaluated using the International Knee Documentation Committee and Lysholm scores. Results: The mean follow-up was 41.15 ± 18.86 and 45.43 ± 21.32 months for the MMAT and LMAT patients, respectively. Concomitant procedures were performed in 90% of MMATs and 15% of LMATs. There was no significant difference between the native and postoperative root positions after LMAT; however, for MMAT, the position of the anterior root was located significantly posteriorly ( P = .002) and medially ( P = .007) compared with preoperatively. In addition, the allograft medial meniscus was restored in a more internally rotated position ( P = .029). MMATs also exhibited significantly increased meniscal extrusion compared with LMATs (posterior horn, P < .001; midbody, P = .027; anterior horn, P = .006). However, there was no significant difference between the 2 groups at final follow-up in intrameniscal signal intensity or clinical scores. Conclusion: LMAT showed higher accuracy than MMAT in restoring meniscal position and rotation, and there was less meniscal extrusion. However, clinical scores improved after both LMAT and MMAT compared with preoperative values, and midterm clinical outcomes were similar. The small anatomical errors seen in the MMAT technique were not clinically relevant at midterm follow-up.

Conflict entails material bases of social life as well as psychological. Conflict resolution is ingrained in the analysis of inter-group dynamics as well as the process and outcome of negotiating different values and incompatible interests. Resolution of serious social conflicts means more than finding solutions to contentious issues. Self-esteem and identity as well as physical well-being are key elements to be considered in conflict resolution and peace building. In rebuilding communal relations, long-term hostile relationships have to be overcome to prevent future occurrences of iolent conflict. According to realpolitik, conflict can be effectively controlled and managed by the use of force or the threat of punishment or retaliation. Conflict resolution is considered a movement toward creating cooperative relationships. Psychological and social dimensions of conflict behaviour were investigated in generating an interdisciplinary theory. Research on conflict resolution ought to be promoted by a holistic approach to examining human conflict.

In this study we investigated racial vs. athletes from other countries, bias and differences in attitude of South Koreans toward advertisements featuring Korean vs. foreign athletes and White vs. Black athletes by implementing explicit and implicit measures. The results suggest that Koreans have: (a) implicit preferences for Korean athletes over foreign athletes, (b) implicit attitudes that are more favorable toward advertisements featuring Korean athletes than toward those featuring foreign athlete-spokespersons, (c) implicit preferences for White athletes over Black athletes, and (d) implicit attitudes that are more favorable toward advertisements featuring White athlete-spokespersons than toward those featuring Black athlete-spokespersons. The explicit measures revealed several contradictory results; therefore we have discussed implications for the discrepancy between implicit and explicit measurement methods and the usefulness of implicit measures in the context of racial bias research.

NEGOTIATION is involved, either at personal, group or international levels, in managing almost every arena of human affairs. In particular, joint solutions are required in many public spheres, both domestic and international, sometimes with grave consequences to the welfare of larger collective communities. Many international actors argue over the terms of settling territorial boundaries, arms control, termination of long-term hostilities, reduced pollution, protection of endangered species, free trade, monetary systems or other shared problems. When more than one solution exists, actors may have different preferences for types of mutually desirable agreements. This produces dilemmas for negotiation. Negotiation is a unique set of social interactions in which negotiators differ but have complementary needs or desires. Facing one of the largest threats to the future of humanity, for instance, every reasonable person would accept the necessity for collective action to reduce greenhouse gas emissions responsible for the irrevocable damage to the global atmosphere, but it has proven difficult for governments to agree to measures to be taken to obtain the objective. Though it has now become part of history (from the 1950s to the early 1990s), the United States and the Soviet Union kept increasing their stockpiles of nuclear weapons the use of which would have left neither side with any chance of survival. Although both sides realized the need to control the arms race through negotiation, they still competed to gain military superiority. It took more than two decades and cost approximately one million lives to end the civil war between the Sudanese government and the south's ‘liberation forces’ prior to the conclusion of a peaceful settlement in 2005. In all these incidents, any one actor's security and welfare cannot be achieved alone, requiring mutually agreed actions. In entering negotiation, each party has certain expectations, but one's objectives cannot be realized without joint solutions to the shared problems. In negotiation settings, a mutually acceptable solution is sought by two or more parties, who have differing preferences over feasible outcomes. Even if the attainment of one party's goals is in fundamental conflict with those of the other parties, negotiation still takes place due to converging interests as well as opposing ones. Incompatible preferences can be resolved through the recognition of the interdependence in which cooperation becomes an inevitable part.

Unless both sides win, no agreement can be permanent. Jimmy Carter, 2002 AS PROGRESS may not necessarily be linear, the potential for negotiations evolves along vastly different trajectories. Nonetheless, the participants should have an overall, even if vague, notion of how the process is likely to proceed. The whole sequence of negotiations can be envisaged as a developmental process of testing the ground, agenda formulation, proposal making, bargaining and closure. In illuminating the main characteristics of different negotiation stages, this chapter looks at specific negotiating activities that encompass proposal exchange, issue redefinition and conceptualization, exploration of an overall structure of the deal, and a search for implementing details. The nature of the dispute is initially defined through issue clarification at the agenda phase. Once having voiced a commitment to key issues, each side has to turn their attention to narrowing the differences before any prospect for settlement emerges. This transition serves as a preliminary to final bargaining. More specifically, these preliminaries constitute a search for a viable range of alternative settlements through a serious study of trading possibilities, and honing a bargaining formula. Jostling for position may precede the eventual ironing out of differences. The points of difference may be narrowed by concession-making. Thus a shared sense of the approximate range of possible terms is essential to deal structuring and detailed bargaining. As vividly illustrated, for instance, in Greek debt talks with Eurozone countries and the US–Iranian nuclear deal-making attempt in 2015, the whole process does not stop at the conclusion of an agreement, spilling over into implementation, demanding either associated negotiation or renegotiation for new or improved terms. Prenegotiation stage As part of prenegotiation dynamics, each side measures the other's capabilities and desires. Then the first step is a decision as to whether or not to negotiate at all. In general, each party should feel compelled to see the need for negotiation; it can be created by various events and other circumstances. The example of Panama's negotiation with the United States below demonstrates how a weaker party can take advantage of a catalytic event to force a much stronger party to see the need to redress their grievances.

If you must be selfish, then be wise and not narrow-minded in your selfishness. Dalai Lama, 2002 NEGOTIATION is often characterized as interdependent actions involving a set of two or more decision-making units which have different preferences over the possible outcomes. By considering a negotiation process as a strategic interaction, we can shed light on interactive decision-making among actors who have a set of actions to choose from. In an interactive process, the actual or likely decisions by one agent have an impact on the other's choice of actions. Viewing this decision-making process within the structure of a game helps us explore different possibilities for solutions to conflicting preferences. In fact, game-theoretic analysis assists in uncovering order in seemingly chaotic interactions among negotiators. This chapter introduces a game-theoretic perspective in building a foundation for understanding structural conditions embedded in many conflict settings. It starts with theoretical assumptions about interactive decision-making and moves on to basic concepts involving the Prisoner's Dilemma and minimax. By introducing these and other concepts such as a dominant strategy and an equilibrium, the chapter lays the groundwork for further discussion about the dynamics of cooperation and conflict that will come later. Strategic interaction in negotiation In strategic situations where the outcome for each participant relies on mutual decisions, an individual's success depends on the choices of others. For instance, when one country concedes part of a disputed territory, they would want to have measures taken to ensure the territory is prevented from being used to attack. Not only one's own choices but also those of other actors drive the allocation of values. In other words, an ability to realize one's own desires hinges on what the other does (Schelling 1960). Thus the outcome derives from mutual influence of each other's actions and strategies, reflecting the decisions of all the concerned parties who have different interests. In general, negotiation has long been defined such that “choices of the actors will determine the allocation of some values,” and “the outcome for each participant is a function of the behavior of the other” (O. Young 1975, 5). More specifically, bargaining takes place because each actor's welfare is affected by the other's decisions.

Life can only be understood backwards, but it must be lived forwards. Soren Kierkegaard, 1843 IN MANY interactive situations, the main concern is for each player to figure out how others will respond to one's own moves and anticipate where their decisions will eventually lead. The games introduced so far have not been adequate at elucidating how a series of moves by each player produces an outcome, as players move at the same time. In a game where players make their decisions simultaneously without knowing the other player's decision, it is interactive only with their current thinking about the other's present move and vice versa. If actions are arranged in a determined temporal order, the sequence of play can be represented in an extensive form displaying a choice at every decision point. It is an important departure from simultaneous games represented in the form of a payoff matrix. In general, a strategy in an extensive form game is constituted by a sequence of actions referred to as moves. In this chapter our main focus is on sequential games that allow the players to move one after another. In tacit bargaining, nonverbal cooperation on a particular solution can arise from a process based on a move and a countermove. The choices of later players are contingent upon the moves made earlier by the other player. This time difference in actions has a strategic effect, as illustrated in the extensive form of a game of Chicken and Battle of the Sexes. At the same time, a player may devise a move outside the defined actions of a given game to gain a strategic advantage. As revealed in the chapter's last section, a chance element needs to be incorporated in the event that players are not able to see all the prior moves made by other players. Sequential games In a sequential-move game, each player sees what their opponent has done before choosing their next action. Having the knowledge of the other players' previous move makes all the difference in a strategic interaction. The order of moves is encapsulated in a decision tree which represents how a game is to be played out over the course of a particular event (O'Neill 1999). A game tree reveals who moves when, and which sequences of actions result in what kind of outcomes.

This study investigated the relationship between the hydrolytic stability and the crystalline regions of cured UF resins with different formaldehyde/urea (F/U) mole ratios to better understand the hydrolysis of cured urea–formaldehyde (UF) resin adhesives responsible for its formaldehyde emission in service. As the F/U mole ratio decreased, the hydrolytic stability of cured UF resins improved, but decreased when the particle size of the resin was reduced. To further understand the improved hydrolytic stability of cured UF resin with lower F/U mole ratios, X-ray diffraction (XRD) was extensively used to examine the crystalline part of cured UF resins, depending on F/U mole ratios, cure temperature and time, hardener type and level. Cured UF resins with higher F/U mole ratios (1.6 and 1.4) showed amorphous structure, while those with lower F/U mole ratios (1.2 and 1.0) showed crystalline regions, which could partially explain the improved hydrolytic stability of the cured UF resin. The crystalline part intensity increased as cure temperature, cure time and hardener content increased. But the 2 θ angles of these crystalline regions did not change, depending on cure temperature and time, hardener type and level, suggesting that the crystalline regions of the cured UF resin were inherent. This study indicates that the crystalline regions of cured UF resins with lower F/U mole ratio contribute partially to the improved hydrolytic stability of the cured resin.

This study investigated the effect of acid hydrolysis on the microstructure of cured urea-formaldehyde (UF) resins using atomic force microscopy (AFM) to better understand its hydrolytic degradation process which has been known to be responsible for the formaldehyde emission of wood-based composite panels. The AFM was scanned on both outer surface and facture surfaces of the thin films of cured UF resins that had been exposed to the etching of dilute hydrochloric acid to simulate their hydrolysis process. The AFM images showed two distinctive parts, which were classified as the hard and soft phases in cured UF resins. For the first time, this study reports the presence of thin filament-like crystalline structures on the fracture surface of cured UF resin. The soft phase of cured UF resins by ammonium chloride was much more easily hydrolyzed than those cured by ammonium sulfate, indicating that hardener types had a great impact on the hydrolytic degradation behavior of cured UF resins. The surface roughness measurement results also supported this result. The results of this study suggested that the soft phase was much more susceptible to the hydrolysis of cured UF resin than the hard phase. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

In an effort to understand the hydrolytic degradation process of cured urea-formaldehyde (UF) resins responsible for the formaldehyde emission of wood-based composite panels, this study analyzed the influ-ence of acid hydrolysis on the morphology of cured UF resins with different formaldehyde/urea (F/U) mole ratios such as 1.6, 1.4, 1.2 and 1.0. Field emission-scanning electron microscopy (FE-SEM) was em-ployed to observe both exterior and fracture surfaces on thin films of cured UF resins before and after the etching with hydrochloric acid as a simulation of the hydrolytic degradation process. FE-SEM images showed that the exterior surface of cured UF resin with the F/U mole ratio of 1.0 had spherical structures after the acid hydrolysis while the other cured UF resins were not the case. However, the fracture surface observation showed that all the samples possessed spherical structures in the cured state of UF resins al-though their occurrence and size decreased as the F/U mole ratio increased. For the first time, we found the spherical structures in cured UF resins of higher F/U mole ratio of 1.4. After the acid hydrolysis, the spherical structures became a much predominant at the fracture surface. These results indicated that the spherical structures in cured UF resinswere much more resistant to the hydrolytic degradation by the acid than amorphous region. Keywords : adhesives, thermosets, morphology, electron microscopy, degradation, structure

As a part of understanding the hydrolysis of cured urea–formaldehyde (UF) resins that has been known as responsible for the formaldehyde emission, leading to sick building syndrome, this study attempted to investigate the morphology and to detect chemical elements of the cured UF resins of different formaldehyde/urea (F/U) mole ratios and hardener (NH4Cl) levels, using field emission-scanning electron microscopy and energy-dispersive spectroscopy. Cured UF resins of low F/U mole ratio showed spherical structure whose diameter increased with an increase in the hardener level, whereas this was not observed for high F/U mole ratio UF resins regardless of the hardener levels. The energy-dispersive spectroscopy results showed five different chemical elements such as carbon, nitrogen, oxygen, chloride, and sodium in cured UF resins. The chloride distribution assumed as the presence of residual acid in the cured UF resins suggested that the hydrolysis of cured UF resins could initiate at the sites of chlorides on the surface of the spherical structures. As the hardener level increased, the quantities of both carbon and oxygen decreased, whereas those of nitrogen and chloride increased as expected. But the quantity of sodium was within measurement error. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

As a part of improving the properties of surface laminates for wood-based panel products, this study attempted to investigate cure kinetics of the melamine–formaldehyde (MF) resin/clay/cellulose nanocomposites. Three different methods (Ozawa, Kissinger, and isoconversion) of differential scanning calorimetry (DSC) were employed to study cure kinetics of the nanocomposites, using three different heating rates (5, 10 and 20 °C/min). Both Ozawa and Kissinger methods showed that the overall activation energy ( E a ) of the nanocomposite at the 0.5 wt% nanoclay level reached a maximum and then decreased thereafter. But, the Ozawa method provided greater E a values than those of the Kissinger method. The isoconversional method provided the change of activation energy ( E α ) values as a function of the degree of conversion ( α ). The E α values increased as the degree of conversion increased, while the influence of nanoclay levels followed a similar trend to the overall E a values from the both Ozawa and Kissinger methods. These results indicated that the exfoliation of layered nanoclay particles into MF resin delayed the cure of MF resin/nanoclay/cellulose nanocomposites.

National reconciliation, while undoubtedly a means to reduce psychological distance and alienation, can be criticized for ignoring basic concerns with justice. Rather than downplayed or smoothed over with political rhetoric, deep structural divisions in post-conflict societies need to be considered in the search for new social identity, meaning, and values. We argue that there can be no “quick fixes” in post-conflict societies and that, to be truly salutary, reconciliation should contribute to the emergence of institutions capable of creatively processing the kind of social tensions that led to past violent conflict.