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This paper investigates the impacts of Northeast Alliance (NEA) between American Airlines and JetBlue Airways on market concentration and airfares on routes to and from the four pertinent airports in Boston and New York regions. Using panel data covering quarterly domestic flight schedules and airfares for 11 U.S. airlines during the 2019–2021 period, we apply difference-in-difference method and find evidence for positive and significant NEA effect on market concentration on routes out of BOS, and negative and significant effect on routes out of EWR, but no significant effect for routes out of JFK and LGA. The overall NEA effects, including all four airports, are not significant. Furthermore, our airfare estimation results indicate that NEA has led to higher airfares on routes out of BOS, JFK and LGA, but not on routes out of EWR. These findings are valuable to supplement the recent antitrust investigation by the U.S. Department of Justice of this alliance. • Investigate the impacts of Northeast Alliance on market concentration and airfares. • Mixed effects on market concentration at different airports concerned. • Mixed effects on airfare at different airports concerned. • Different airfare increasing effects between American Airlines and JetBlue Airways. [ABSTRACT FROM AUTHOR]

This analysis aimed to investigate gender differences in adolescents' concerns and the health implications of COVID-19. We used two rounds of the Global Early Adolescent Study (GEAS) collected in Shanghai in 2018 and 2020. We analyzed data from 621 adolescents, comparing boys' and girls' concerns about COVID-19 and examining trends in general health and mental health by sex between the pre-COVID-19 and COVID-19 periods. Changes in health indicators over time were assessed using generalized estimating equation (GEE) models. Adolescent girls reported more health concerns (52.0% vs. 42.7%) and educational concerns (61.0% vs. 46.3%) than boys, whereas boys expressed more worries about the economic consequences of COVID-19 (32.9% vs. 25.4%). Changes in health-related outcomes during the pandemic compared to the prepandemic era differed by sex and varied by COVID-related experiences. Boys reported improved overall health (OR: 1.54, 95% CI: 1.00, 2.35) in the COVID-19 period relative to the pre-COVID-19 period. Such improvements were only observed among boys who reported no family economic hardships (OR: 2.10, 95% CI: 1.24, 3.58). We found no significant change for girls (OR: 1.14, 95% CI: 0.83, 1.55), regardless of COVID-19 economic impacts. In contrast, girls reported increased anxiety (OR: 1.63, 95% CI: 1.09, 2.45), especially among those who were concerned about their academic performance (OR: 1.85, 95% CI: 1.16, 2.97). Boys experienced no such increase (OR: 0.92, 95% CI: 0.55, 1.54), regardless of their education concerns. Adolescents' COVID-19 experiences are highly gendered and result in increased health inequalities, with greater mental health implications for girls. [ABSTRACT FROM AUTHOR]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jue.2008.03.001 Byline: Tae H. Oum (a)(b), Jia Yan (c)(d), Chunyan Yu (a) Keywords: Ownership forms; Airports; Translog cost system; Stochastic frontier; Bayesian approach Abstract: We study the effects of ownership forms on airports' cost efficiency by applying stochastic frontier analysis to a panel data of the world's major airports. Our key findings are: (a) Countries considering privatization of airports should transfer majority shares to the private sector; (b) Mixed ownership of airport with a government majority should be avoided in favor of even 100% government owned public firm; (c) US airports operated by port authorities should consider to transfer ownership/management to independent airport authorities; and (d) Privatization of one or more airports in cities with multiple airports would improve the efficiency of all airports. Author Affiliation: (a) Sauder School of Business, The University of British Columbia, 2053 Main Mall, Vancouver, BC, Canada V6T 1Z2 (b) College of Business, Embry Riddle Aeronautical University, 600 S. Clyde Morris Blvd, Daytona Beach, FL 32114, USA (c) School of Economic Sciences, Washington State University, Hulbert 101, Pullman, WA 99164, USA (d) Faculty of Business, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, PR China Article History: Received 12 April 2007; Revised 3 March 2008

The impact that strategic alliances have on business performance is an important topic of alliance research. The study conducted based on panel data from 22 international airline companies, which formed alliances during the period 1986-1995 revealed that horizontal alliances make a significant contribution to productivity gains, whereas they have no overall significant and positive impact on profitability.

The purpose of the study is to assess the prevalence of pornography use and its association with a range of perceived gender norms among adolescents aged 10–14 years across five urban poor settings globally. The study includes 9,250 adolescents aged 10–14 years from Belgium, China, the Democratic Republic of the Congo, Ecuador, and Indonesia, as part of the Global Early Adolescent Study. We examined the percentage of pornography use by sex and site and conducted multivariate logistic regressions to examine the relation between gender norm perceptions and pornography use, adjusting for individual, family, peer, and media exposures. Ever-use of pornography ranged from 14.5% in Ecuador to 33.0% in Belgium and was more common among boys than girls. Overall, boys who perceived greater permissiveness about romantic relations, adolescents who engaged in such relations, and adolescents who assumed that their friends were sexually active had greater pornography exposure. Pornography use did not systematically correlate with unequal gender norms. Such correlations only exist among boys in two Asian sites, where a supportive school environment, more caregiver awareness, and/or neighborhood cohesion were related to less pornography use. Pornography use is a gendered experience that begins in early adolescence. Although factors of pornography use vary across the social context, the exposure to pornography has become a normative part of adolescent sexuality development. Young people, especially those from where sexuality remains taboo, need the ability to critically process information and avoid potential risks associated with pornographic gendered and sexual stereotypes, calling for comprehensive sexuality education programs to help them build the knowledge and confidence they need. [ABSTRACT FROM AUTHOR]

This paper used data from the Global Early Adolescent Study (GEAS) to provide a descriptive analysis of how early adolescents' social environments vary by sex across diverse cultural settings. The analyses were based on baseline data among 10–14-year old adolescents living in disadvantaged urban areas in seven sites: Kinshasa (DRC), Shanghai (China), Cuenca (Ecuador), Lampung, Semarang and Denpasar (Indonesia), and Flanders (Belgium). Except in Kinshasa where face-to face interviews were used, data were collected using self-administered surveys on mobile tablets. Social environments were measured by examining factors within five main domains, including the household and family, school, peers, neighborhoods, and the media. Site-specific descriptive analyses were performed, using Chi square tests and Student T-tests to identify sex-differences in each site. The majority of early adolescents lived in two-parent households, perceived their parents/guardians cared and monitored them, had at least one friend, reported high educational aspirations, and perceived their neighborhoods as safe, socially cohesive, with a high level of social control. Yet, large gender and site differences were also observed. More girls reported same-sex friends and high levels of parental monitoring, while boys were more likely to have mixed-sex friends and spend greater amounts of time with friends. Adolescents in Kinshasa and Semarang watched the most TV per day, while higher proportions of adolescents in Flanders used social media on a daily basis. Significant gender differences in media use were also observed but varied according to site. Understanding how social contexts differ between boys and girls across sites has relevance for how we might examine gender attitude formations and subsequent health behaviors. Given the increased attention on the importance of early adolescence for shaping gender attitudes and norms, implementing approaches that consider the differences in boys' and girls' lives may hold the most promise for creating sustained and improve change. [ABSTRACT FROM AUTHOR]

This paper estimates the impact of the U.S.-China trade war and the consequent increase in trade costs on air and ocean shipments between the two countries. Using panel data covering U.S. exports and imports with its trading partners from 2016 to 2021, we estimate gravity models and find evidence showing negative impacts of the trade war on both U.S. imports from China and U.S. exports to China. However, there are differential impacts on air shipments and ocean shipments. Specifically, we find that U.S. tariff increases on Chinese goods primarily had a negative effect on air imports from China, whereas China's retaliatory tariffs on U.S. goods mainly had a negative impact on U.S. ocean exports. These findings contribute to the growing body of evidence on the effects of the U.S.-China trade war, highlighting the varying impacts of the trade war on different modes of transportation that drive the U.S.-China trade relationship. • The impacts of the U.S. – China trade war on air and ocean shipments are estimated using gravity models. • The trade war had differential impacts on air shipments and ocean shipments between the U.S. and China. • The trade war significantly decreased U.S. ocean shipments to China. • The trade war significantly decreased Chinese air shipments to the U.S. [ABSTRACT FROM AUTHOR]

This paper studies the market entry patterns and evolving strategies adopted by Southwest and JetBlue. Based on the quarterly data from US T100 Domestic Segment database, we trace Southwest's successful market entries from 1993 to 2016, and those of JetBlue from 2000 to 2016, and estimate a set of discrete choice models to investigate the factors that may attract or deter route entries by Southwest and JetBlue. These factors reflect route distance, traffic demand, market power of the carriers, route competition, and connectivity and traffic concentration at endpoint airports, etc. The paper also examines the similarity and dissimilarity between Southwest and JetBlue with respect to the effects of these factors on their entry decisions, and how their route entry decisions have evolved over time. Our results indicate that both Southwest and JetBlue are more likely to enter routes where they have higher market share in terms of traffic and connectivity at endpoint airports, but they are less likely to enter routes involving endpoint airports with higher concentration in either traffic or connectivity. While Southwest appears to prefer routes with short to medium distance in the 1990s, it has started to target longer distance routes since 2000. JetBlue has consistently preferred longer distance routes. While the number of legacy rivals on a given route may deter market entry by Southwest, it does not appear to have any significant effect on the entry decisions by JetBlue. Moreover, the presence of other LCCs may have deterred the market entry by Southwest during the 1993–1999 period, and by JetBlue during the 2000–2006 period, its entry-deterrence effects has been becoming less important as the two airlines continue their growth and market expansion. The results further suggest that Southwest has continued to be hesitant to enter routes that have asymmetric traffic volume at endpoint airports, but it has become more drawn to routes with broader connections and higher traffic at endpoint airports as it moves into the business passenger segment. [ABSTRACT FROM AUTHOR]

Recurrent Neural Networks (RNNs), known for handling complex data tasks like language translation and speech recognition, are seldom employed in airport management practice for daily and weekly passenger flow forecasting tasks. In this paper, we evaluate the effectiveness and adaptability of various neural network models (RNN, LSTM, GRU, Deep LSTM, Bidirectional LSTM, multivariate RNN, and multivariate LSTM) against standard time series models (ARIMA, SARIMA, and SARIMAX) for a short-term forecasting airport security checkpoint passenger flows at five major U.S. airports during the pandemic. At Atlanta's Hartsfield-Jackson Airport (ATL), the RNN notably surpasses SARIMA's forecasting accuracy by 34% (DM = 3.44, p < 0.01). This underscores RNN's superiority in handling complex interactions among variables and non-linear dynamics, demonstrating its readiness for the emerging data-rich environment. Including exogenous variables enhances the forecasting accuracies of the multivariate RNN/LSTM (DM = 6.82, p < 0.01; DM = 2.65, p < 0.01, respectively), while the SARIMAX struggles with the added complexity. We observed the same patterns at the other four airports studied (DEN/ORD/LAX/DFW) during the pandemic period. However, during the normal airport traffic period, the clear superiority of RNN became much less pronounced, obscuring the performance gap between RNN and SARIMA. This suggests that the inherent advantages of RNN in capturing non-linearity are accentuated during volatile conditions and less pronounced or not pronounced at all during routine periods. • RNNs are viable alternatives to time series models (ARIMA, SARIMA) to forecast airport passenger flow in airport management. • The study evaluates various neural network models for airport passenger flow forecasting. • RNN surpasses SARIMA by 34% in forecasting accuracy at Atlanta's Hartsfield-Jackson Airport. • Including exogenous variables enhances multivariate RNN/LSTM forecasting accuracy, while SARIMAX struggles with complexity. • Consistent superior RNN forecasting was observed and validated across five major U.S. airports, implying broad applicability. [ABSTRACT FROM AUTHOR]

Hemostatic materials are of great significance for rapid control of bleeding, especially in military trauma and traffic accidents. Chitosan (CS) hemostatic sponges have been widely concerned and studied due to their excellent biocompatibility. However, the hemostatic performance of pure chitosan sponges is poor due to the shortcoming of strong rigidity. In this study, CS and hydroxypropylmethylcellulose (HPMC) were combined to develop a safe and effective hemostatic composite sponges (CS/HPMC) for hemorrhage control by a simple mixed-lyophilization strategy. The CS/HPMC exhibited excellent flexibility (the flexibility was 74% higher than that of pure CS sponges). Due to the high porosity and procoagulant chemical structure of the CS/HPMC, it exhibited rapid hemostatic ability in vitro (BCI was shortened by 50% than that of pure CS sponges). The good biocompatibility of the obtained CS/HPMC was confirmed via cytotoxicity, hemocompatibility and skin irritation tests. The CS/HPMC can induced the erythrocyte and platelets adhesion, resulting in significant coagulation acceleration. The CS/HPMC had excellent performance in vivo assessments with shortest clotting time (40 s) and minimal blood loss (166 mg). All above results proved that the CS/HPMC had great potential to be a safe and rapid hemostatic material. [ABSTRACT FROM AUTHOR]

A highly selective synthesis of conjugated polyene sulfonyl derivatives is described via the elimination of disulfonyl chloride with readily accessible raw material dihaloalkane. The protocol offers a convenient way to form sulfonamides, sulfonates and even sulfones. Furthermore, this method was manipulated under mild condition with simple operation in high yield to afford only trans products. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to demonstrate that user-generated online contents can be used as an alternative data source for assessing airport service quality, which effectively complements and cross-validates the conventional service quality surveys. We apply sentiment analysis and topic modeling technique to 42,137 reviews collected from Google Maps. The results are compared to the well-publicized ASQ ratings conducted by Airport Council International. The sentiment scores computed from the textual Google reviews are very good predictors of the associated Google star ratings, with r s (96) = 0.89, p  < .01 in 2016. The correlation could be further improved ( r s (96) = 0.90) by customizing the sentiment lexicon leveraging the information gained from the previous year's analysis. Also, both the sentiment scores and Google star ratings are found to have a reasonably strong association with the ASQ ratings, with r s (78) = 0.63, p  < .01 and r s (78) = 0.64, p  < .01, respectively, in 2016, excluding outliers. These results indicate that the online reviews provide a good proxy for airport service quality ratings and an effective means to cross-validate the conventional industry standard survey results. Further, the study extracts 25 latent topics from the Google reviews through a topic modeling analysis. The 25 topics show good correspondence with the ASQ service attributes, suggesting that the ASQ program effectively covers all the service quality attributes of airport users. Also, further analysis indicates that the relative importance of service attributes varies depending on the size of the airports and that some ASQ service attributes may not be relevant anymore for most passengers. [ABSTRACT FROM AUTHOR]

Using a panel data for Southwest and JetBlue in the 1st quarter of 2009, 2011, and 2013, we develop an empirical study and find evidence suggesting that the amount of bag fee charged by bag fee airlines, including those direct rivals at the route level and indirect rivals competing from adjacent airports, has a positive and significant effect on the airfare of non-bag fee airlines and such a positive association is smaller on vacation-oriented routes, but greater on routes with higher per capita income at endpoint cities. Moreover, the results are found that on the routes where Southwest is the only non-bag fee airline, the amount of bag fee charged by other airlines has a positive and significant effect on the traffic volume of Southwest. This traffic increasing effect, however, may be offset by the higher airfare of Southwest in response to other airlines’ imposition of bag fees. [ABSTRACT FROM AUTHOR]

We examine short-haul services offered by the respective 10 largest European and North American carriers in terms of fleet composition, network characteristics, airfare and product attributes. Our cross-business model and cross-continental analysis builds on the index approach developed by Klophaus et al. (2012) to derive a typology of the hybridization among the largest carriers in Europe and North America in short-haul markets. Our results indicate that none of the largest European and North American carriers follows the pure LCC business model in short-haul markets, and all the LCCs in Europe and North America have adopted certain degree of hybrid strategy to offer short-haul services combining business practices traditionally considered typical for FSCs or LCCs. The results also confirm the categorization of most of the carriers labelled as FSCs. In addition, the study provides evidence of further convergence of airline business models in the short-haul market during the last decade. Still there is no standard short-haul business strategy despite common industry standards for some service features. • Our cross-business model and cross-continental study examines airline services in short-haul markets. • Convergence of FSC and LCC short-haul airline services is more pronounced in North America than in Europe. • There is still no standard short-haul business strategy despite some common industry service attributes. • All of the largest LCCs in Europe and North America have adopted a hybrid business strategy. • North American ULCCs deviate more from the LCC business model than non-affiliated European LCCs. [ABSTRACT FROM AUTHOR]