Oligopolistic Agreement and/or Superiority?: New Findings from New Methodologies and Data

The influential Scherer and Ross text (1990, p. 411) states that the main question in empirical industrial organization in the latter part of the twentieth century is Bains (1951) collusion or agreement hypothesis versus Demsetzs (1973) superior firm hypothesis. Prior to the Federal Trade Commission Line-of-Business (LOB) studies the contending schools were deadlocked, but these studies led to a win being declared for the superiority hypothesis by Scherer writing with seven other LOB researchers (1987). These studies found that the effect of concentration on profits disappeared when controlling for firm shares. As many economists agreed, merger policy shifted away from a focus on agreement to applying a unilateral effects (non-cooperative Nash) approach. We develop a nine year panel LOB data set for Korea. We perform three types of tests, all of which support both hypotheses, but which show that the agreement effect overwhelmingly dominates the superiority effect in pricing. First we examine a secondary implication of the superiority model: profit aggregation should imply that if share is negatively related to firm profits, so should concentration be negatively related to industry profits. Instead, we find that for those industries with a negative share relationship, the concentration profits relationship is positive and virtually identical to the relationship for the full sample in both within and between panel tests. Next we introduce a commonly cited model in the empirical literature. This model is cited to motivate the proposition that both share and concentration should have an effect on firm profits. However, authors who cite this model then typically use an ad hoc specification rather than estimating this as a structural model. We develop our structural model and define latent variables to distinguish between domestic and export price cost margins (PCMs) and to identify firm conjectures as they impact the domestic PCM. Demand elasticities are captured in non-linear industry fixed effects. We show that concentration plays an overwhelming role in determining firm PCMs, with firm share playing a far smaller role. We additionally exploit the structural characteristics of the model to deal with the possibility that deviations between marginal costs and average costs might be driving the results. For supporting evidence we construct a new latent variable identifying the domestic/export price ratio. We find a strong within relationship between concentration and the domestic/export price ratio, again firm shares play a weaker role. Finally, we discuss why our results differ from the FTC-LOB studies and provide evidence that would suggest that the FTC studies conclusions are biased due to the 1973 removal of price controls and energy crisis, the stagflation of the 1970s, and the use of national firm shares along with geographically weighted averages of concentration ratios.Industrial Organization,

A study of the causal relationship between IT governance inhibitors and its success in Korea enterprises

노트 : Proceedings of the 41st Hawaii International Conference on System Sciences - 2008 행사명 : 41st Hawaii International Conference on System Sc

Identification of predictive variables for the recurrence of oral mucocele

Oral mucocele is the most common minor salivary gland lesion with good prognosis after surgical removal. However, its recurrence is not rare, sometimes bothersome. This study aimed to identify the possible predictive variables affecting the recurrence rate of oral mucocele. The histoclinical data of 164 patients diagnosed with oral mucocele were retrospectively obtained by reviewing dental records. The predictive variables for its recurrence were identified by analyzing its recurrence rate according to clinical variables. The recurrence rate showed the significant differences according to location and age. Oral mucocele recurred with significantly higher frequency on the ventral mucosa of tongue (50.0%) than on the labial/buccal mucosa (8.8%). Its recurrence was significantly more common in the younger patients (aged 30 years, 4.4%). However, there was no significant difference in recurrence rates between surgical procedures using scalpels and those using lasers. Patients with oral mucocele should be more carefully informed of its possible recurrence, especially when it is found on the ventral surface of the tongue or in a younger population

The Formation and Differentiation of Modern Korean Music World

Translated from the article published in Culture and Society, vol. 10, 2011, with permission from the Korean Association for Sociology of CultureThis study examines the formation and characteristics of modern music world in colonial Korea during the 1930s. Modern Korean music world inherited the legacy of traditional Korean music, but at the same time was heavily influenced by the newly introduced western music and Japanese popular music. In analyzing the formation of music world, we focus on the dynamics between different musical genres and also on the relationships between composers and singers. Social Network Analysis of two-mode data on genre-singer, genrecomposer, and composer-singer networks reveals that boundaries between genres became more established over time and that the relationship between composers and singers show limited stability reflecting the high level of uncertainty in the market of popular music

Atopic Dermatitis-Like Skin Lesions Reduced by Topical Application and Intraperitoneal Injection of Hirsutenone in NC/Nga Mice

Atopic dermatitis (AD) is a common inflammatory skin disease. The increasing prevalence and severity of AD have prompted the developments of safer, more effective drugs. Although topical corticosteroids have been used as first line therapy for AD, their potential side effects limit their clinical applications. To investigate the effect of hirsutenone (HIR), a diarylheptanoid compound, on AD-like skin lesions and other factors related to immune response is the aim of this paper Th2-related cytokines (IL-4, IL-5, IL-13), eosinophil, IgE inflammatory factors (COX-2, iNOS) levels were reduced in blood, lymphocytes, and tissue after HIR treatment. These results suggest that HIR might be an effective treatment for AD

Anatomical Consideration of the Anterior and Lateral Cutaneous Nerves in the Scalp

To better understand the anatomic location of scalp nerves involved in various neurosurgical procedures, including awake surgery and neuropathic pain control, a total of 30 anterolateral scalp cutaneous nerves were examined in Korean adult cadavers. The dissection was performed from the distal to the proximal aspects of the nerve. Considering the external bony landmarks, each reference point was defined for all measurements. The supraorbital nerve arose from the supraorbital notch or supraorbital foramen 29 mm lateral to the midline (range, 25-33 mm) and 5 mm below the supraorbital upper margin (range, 4-6 mm). The supratrochlear nerve exited from the orbital rim 16 mm lateral to the midline (range, 12-21 mm) and 7 mm below the supraorbital upper margin (range, 6-9 mm). The zygomaticotemporal nerve pierced the deep temporalis fascia 10 mm posterior to the frontozygomatic suture (range, 7-13 mm) and 22 mm above the upper margin of the zygomatic arch (range, 15-27 mm). In addition, three types of zygomaticotemporal nerve branches were found. Considering the superficial temporal artery, the auriculotemporal nerve was mostly located superficial or posterior to the artery (80%). There were no significant differences between the right and left sides or based on gender (P>0.05). These data can be applied to many neurosurgical diagnostic or therapeutic procedures related to anterolateral scalp cutaneous nerve