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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.

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]

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]

Drug-delivery technology is an effective way to promote drug absorption and efficacy. Mesoporous hollow silica material and small-molecule drug ibuprofen were used as a carrier model and as model drug, respectively. By quantum chemical calculation (density functional theory and frontier orbital theory), it was found that the content of geminal silanols on the material surface played a decisive role in the release of the different drugs. The rough hollow materials are easily adsorbed and have a large loading capacity, and so we fabricated a mesoporous hollow silica material (R-nCHMSNs) with a rough surface and rich geminal silanols by using hydroxyl-rich nanocellulose as a template. The content and types of hydroxyl groups on the material surface were studied by 29Si NMR. The loading and delivery of ibuprofen and lysozyme were studied in detail. Materials with rich geminal silanols exhibited excellent delivery properties for different drugs, which shows great potential and research value for drug delivery. [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]

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]

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]

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]

This study aimed to explore the desirable characteristics of casein hydrolysates with simultaneously enhanced emulsion forming and antioxidative ability in oil-in-water (O/W) emulsion. Effects of physicochemical properties of casein hydrolysates prepared by trypsin, alcalase, and neutrase on physical and oxidative stability of O/W emulsion were studied, and potential antioxidant peptides were characterized by UPLC-MS/MS and bioinformatics analysis. Results showed that casein hydrolysates at a lower degree of hydrolysis (DH) produced by trypsin displayed higher zeta potential absolute values (−31.7 mV), smaller particle size (170.75 nm) and improved antioxidant properties compared to alcalase and neutrase, and could form more stable emulsion with d 4,3 of 0.39–0.41 μm at a broader range of DH. Additionally, compared with sodium caseinate (NaCas), the oxidation of emulsion was significantly retarded during the storage progress prepared by the trypsin hydrolysates at DH of 4.49% alone or with Tween 20. Peptidomics indicated that the trypsin hydrolysates contained more peptides with basic amino acids at C-terminal and aromatic amino acids at N-terminus, which exhibited cationic amphiphilic properties with grand average of hydrophilicity values (GRAVY) of −0.5 ∼ +0.5 and pI > pH 7.0. This could contribute to their better emulsion formation and inhibition of lipid oxidation ability by producing dense interfacial layers with peptides interactions or excluding metal ions in O/W emulsions. These results suggested that casein hydrolysates at lower DH prepared by trypsin owned potential amphiphilic antioxidant peptides, which were desired to enhance the stability and functional activity of O/W emulsion. [Display omitted] • Trypsin hydrolysates featured specificity in zeta value and particle size at low DH. • Casein hydrolysates exhibited better emulsion formation ability at low DH. • Trypsin hydrolysates at low DH effectively retarded lipid oxidation. • More cationic amphiphilic peptides were observed in trypsin hydrolysates. [ABSTRACT FROM AUTHOR]

We develop two air traffic seasonality indices to complement the traditional Gini index. These measurements are adopted to assess the variability of air traffic over time and across the route network of low-cost carriers (LCCs) in Europe and the United States and to estimate the impact of seasonality on fleet utilization. Using panel data for nine LCCs in Europe and the United States from 2004 to 2017, we find that higher seasonality results in lower fleet utilization after controlling for stage length, network size, aircraft size, and fleet standardization. Moreover, we find that seasonality is negatively associated with spatial and climate zone diversification of airline route networks. These results suggest that airlines may be able to reduce seasonal traffic variability through diversifying their networks geographically and consequently mitigating the negative fleet utilization impact. • Alternative seasonality measures are developed for measuring the temporal-spatial characteristics of air traffic variability. • The relationship between air traffic seasonality and climate diversification of airline route network is empirically studied. • Seasonality is found to have a negative effect on fleet utilization based on panel data estimation. • Köppen values are employed for measuring climate diversification of an airline's route network. [ABSTRACT FROM AUTHOR]

Phenylcoumaran benzylic ether reductase (PCBER) in the phenylpropane metabolic pathway plays a crucial role in controlling plant growth and development. However, its biological function in response to abiotic stress in perennial trees is still largely obscure. In this work, a phenylcoumaran benzylic ether reductase gene, PtPCBER , isolated from poplar was overexpressed in poplar. The growth and salt resistance of transgenic plants were investigated, and the possible regulatory mechanism of PtPCBER in response to abiotic stresses was verified. PtPCBER was constitutively expressed in various tissues and organs with a predominant expression in xylems. Overexpression of PtPCBER augmented the salt and oxidative stress tolerance of transgenic poplar plants. The increased salt tolerance was associated with a relatively lower chlorphyll loss and Na+ accumulation, and a higher antioxidant enzyme activity and stress gene expression, in the leaves of transgenic plants. Further metabolomic analyses revealed that overexpression of PtPCBER cut down the accumulation of coniferyl alcohols and lignans which function in the reactive oxygen species (ROS) scavenging pathway to alleviate the damage caused by oxidative stress in the leaves of transgenic plants. Taken together, our results suggest that PtPCBER has an important function in plant response to salt stress, and it could be used as an ideal candidate gene for the genetic engineering of woody plants with enhance resistance to multiple abiotic stresses through improving the scavenging capacity of ROS. • Overexpression of PtPCBER promoted salt tolerance in transgenic poplar. • The salt tolerance of transgenic plants was associated with ion homeostasis changes. • The reactive oxygen species scavenging capacity was increased in transgenic poplar. [ABSTRACT FROM AUTHOR]

Accidental marine oil spill pollution can result in severe environmental, ecological, economic and other consequences. This paper discussed the model of Marine Oil Spill Risk Mapping (MOSRM), which was constructed as follows: (1) proposing a marine oil spill risk system based on the typical marine oil spill pollution accidents and prevailing risk theories; (2) identifying suitable indexes that are supported by quantitative sub-indexes; (3) constructing the risk measuring models according to the actual interactions between the factors in the risk system; and (4) assessing marine oil spill risk on coastal city scale with GIS to map the overall risk. The case study of accidental marine oil spill pollution in the coastal area of Dalian, China was used to demonstrate the effectiveness of the model. The coastal areas of Dalian were divided into three zones with risk degrees of high, medium, and low. And detailed countermeasures were proposed for specific risk zones. [ABSTRACT FROM AUTHOR]

To elucidate the effect of nitrite ion (NO 2 − ) on the photodegradation of organic pollutants, a 300 W mercury lamp and Pyrex tubes restricting the transmission of wavelengths below 290 nm were used to simulate sunlight, and the photodegradation processes of 2,4-dichlorophenoxyacetic acid (2,4-D) with different concentrations of NO 2 − in freshwater and seawater were studied. The effect of reactive oxygen species (ROS) on the photolysis of 2,4-D was also demonstrated using electron paramagnetic resonance (EPR). The results indicated that the 2,4-D photolysis reaction followed the first-order kinetics in freshwater and seawater under different concentrations of NO 2 − . Meanwhile, the photochemical reaction rate of 2,4-D increased with increasing concentration of NO 2 − . When the concentration of NO 2 − was lower than 23 mg/L, the photodegradation rate of 2,4-D in seawater was higher than that in freshwater. However, when the concentration of NO 2 − was reached 230 mg/L, 2,4-D degradation slowed down in seawater. It was important to note that EPR spectra showed NO 2 radical was generated in the NO 2 − solution under simulated sunlight irradiation, indicating that 2,4-D photodegradation could be induced by NO 2 . These results show the key role of NO 2 − in photochemistry and are helpful for better understanding of the phototransformation of environmental contaminants in natural aquatic systems. [ABSTRACT FROM AUTHOR]

Abstract: This paper applies an inventory transshipment modeling approach to investigate the air cargo revenue management problem for an airline operating in a two-segment network. Building upon an extension of the classic two-location inventory transshipment model, we develop a framework to optimize an airline’s cargo overbooking decisions in a two-segment network setting. We find consistent evidence indicating that network-based global optimization always leads to greater expected profits than does local (i.e., market by market) optimization. Further, the magnitude of profit improvement is found to be most significant when local shipments have a relatively higher freight yield compared to flow-through shipments. Finally, our results indicate that global optimization contributes to greater profit improvement as offloading penalty costs become higher. [Copyright &y& Elsevier]

This paper evaluates the relationship between corruption and operational efficiency of airports in Asia, by analyzing a panel dataset of 26 Asian airports over the 2003–2019 period. Our estimation results for Asia confirm the findings for other regions that there exists a negative association between the operational efficiencies of airports and the corruption level in the country. Airports owned, operated and/or managed by government corporations (100% government) are the most affected, in that they experience significant loss of efficiency when located in a high corruption country. The residual variable factor productivity (RVFP) from the Air Transport Research Society (ATRS) airport benchmarking reports is used as measure of airport operational efficiency. Regression analyses are applied to evaluate the relationship between airport efficiency and corruption. The results are robust to alternative corruption indexes. The findings of this paper have important policy implications for the management of large public infrastructure projects and airport governance reforms in Asia. • We assess the impact of corruption on airport efficiency in Asia. • The dataset covers 26 airports located in 10 Asian countries over the 2003–2019 period. • Residual Variable Factor Productivity is used as measure of airport efficiency. • Analyses show a negative association between airport efficiency and corruption in Asia. • Corruption impacts are stronger for airports under public corporations. [ABSTRACT FROM AUTHOR]

Abstract: GaN nanomaterials are displaying infinite develop potential in blue light-emitting diode (LED).Therefore, the preparation of low-cost and high-powered GaN nonmaterial has been one of the focuses for scientific researchers. It is known that different catalysts have different impacts on the surface and function of GaN in the process of preparation. Therefore the proper catalysts must be selected to grow GaN nanostructure with high-quality and performance. In the present study, the effects of different catalysts on the surface and function of GaN have been summarized. Those catalysts includes Ni, In, Au, Ag, and so on. Furthermore, the advantages and disadvantages of those catalysts have been overviewed. [Copyright &y& Elsevier]

Abstract: This paper tests the mutual forbearance view in the context of airline alliances in the international air travel market. Using passenger booking and airfare data on transpacific routes, we find consistent evidence for the positive association between multimarket contact and airfares. Our results also suggest that multimarket contact between non-aligned airlines is associated with higher airfares, whereas multimarket contact between airlines in the same alliance has no additional upward impact on airfares. Moreover, it is shown that higher airfares tend to exist when airlines have greater multimarket contact on open-skies routes. In restrictive (non-liberal) international markets, however, multimarket contact may not affect airfare. [Copyright &y& Elsevier]

Studies on airport performance have focused primarily on productivity and operational efficiency. There are very few studies on airports' financial viability and strength, especially those in the United States. Most of the U.S. commercial service airports are government-owned entities and operated for the service of the community rather than for profit, but expected to be financially self-sufficient and raise capital funds mainly through the bond markets. However, past studies of the financial performance of U.S. airports have relied on traditional profitability measures and financial efficiency measures that are more appropriate for airports owned and operated by for-profit entities. Based on the literature for non-profit organizations and the practices of credit rating agencies and government oversight bodies, this paper adopts six pertinent financial performance metrics to measure and compare the operational financial performance, leverage, and liquidity of 60 large and medium commercial service airports in the United States during the 2010–2017 period. The paper further examines factors that may affect airport financial performance. The results reveal that large hub airports have better liquidity while medium airports have better leverage during the study period. These results suggest that the effect of airport size on financial performance is inconclusive. Regression analysis shows that airports with high productive efficiency and those without a dominant carrier tend to have more surplus revenues for meeting their operational financial needs and capital spending and have better liquidity. The paper highlights the importance of using appropriate metrics to evaluate the financial performance of public sector entities and provides relevant information to bond investors. The devastating impacts of the COVID-19 pandemic on airports accentuate the significance of leverage and liquidity. Therefore, the financial metrics discussed in this paper would help support public policy debates and allocate public funds to the airports. • Discusses financial performance metrics of large and medium commercial service airports in the U.S. for the 2010–2017 period. • Financial ratio analysis reveals that large hub airports have stronger liquidity while medium airports have better leverage. • Analysis puts focus on the appropriate financial metrics for U.S. airports relevant to policy makers and investors. [ABSTRACT FROM AUTHOR]

Airline productivity and efficiency have remained an area of tremendous interest among both academics and industry analysts since the Airline Deregulation Act of 1978 was enacted in the United States. This paper provides a bibliometric analysis of airline productivity and efficiency studies during the period from 1979 to 2020. The results show that the Journal of Air Transport Management , Transportation Research Part A , and Transportation Research Part E were the top three outlets preferred for publications in this area during the study period, and productive authors were likely to produce influential works. Research interest in airline productivity and efficiency has spread to encompass more diversified geographical regions over time, and new researchers from a broad range of fields continue to become interested in this field of research. Data envelopment analysis and stochastic frontier analysis are shown to be the most popular methods used by researchers, and studies are increasingly attempting to incorporate undesirable outputs, such as carbon emissions, flight delays and accidents, into the measurement and analysis of airline performance. The results from this study can provide guidance for future research issues and directions. • This paper aims to review airline efficiency studies using bibliometric approach. • JATM, TR-A and TR-E have been the top three outlets preferred for publications. • Research interests have spread to encompass more diversified geographical regions. • Incorporating undesirable outputs has becoming a trend in airline efficiency studies. [ABSTRACT FROM AUTHOR]