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The aim of this paper is to examine how a shock in the oil industry affects firms’ debt funding obligations using credit default swaps in different segments of the oil industry’s value chain. In particular, it focuses on two types of shocks suffered by upstream, integrated and downstream firms in the industry, namely (1) endogenous shocks resulting from oil-market shocks, and (2) exogenous shocks resulting from the recent financial crisis and the Covid-19 pandemic. Using a wide data set ranging from 2007 to 2020, this paper measures the dynamic relationships between the CDS spreads of oil-related firms, US dollar exchange rates, and crude oil prices at different sectors of the oil-industry value chain, namely, upstream, integrated and downstream. Overall results show that the upstream firms have suffered the largest impacts during the COVID-19 crisis, when experiencing shocks from USD rates or oil prices. Integrated firms have suffered the second-largest effects, however, and interestingly, no significant impacts from shocks are observed on CDS spreads for downstream firms.

Drawing upon signaling theory and social identity theory, we developed a theoretical model that illuminates the role of brand credibility as an important basis on which customers form and signal their brand-related self and social identities via positive word-of-mouth (WOM). The proposed model was empirically tested using time-lagged data from a sample of 249 students of a top university in a metropolitan city. The findings show that the credibility of a brand is of paramount importance for the customer in developing a sense of oneness with the brand as well as a sense of affinity with other users of the brand. Our study also offers the new insight that brands serve as symbolic devices that customers use in their evolving thought processes that create a link between personal identity and social identity. In addition, brand–social connection is essential in spreading positive WOM. Finally, our findings support a sequential mediation model in which brand credibility is positively related to brand–self connection and brand–social connection, which in turn are positively associated with positive WOM.

Purpose The purpose of this study is to explore how emotions felt by the public during a crisis influenced consumer loyalty intention and negative word-of-mouth (WOM). Considering the context-specific nature of emotions, the existing crisis emotions were further validated in a product consumption situation. Drawing on the theories of attribution and social sharing, a conceptual model, positing that crisis-specific emotions [attribution-independent, external-attribution-dependent (EAD) and internal-attribution-dependent (IAD) emotions] influenced negative WOM through behavioural intention, was constructed and empirically tested. Design/methodology/approach Data was collected from 240 Vietnamese consumers by using a scenario-based survey related to a fictional milk crisis. Findings The study findings showed that all but one crisis emotion had negative effects on both WOM and loyalty intention. Of these emotions, EAD and IAD were the strongest predictors of negative WOM and behavioural intention, respectively. It was also found that all crisis emotions significantly affected negative WOM through behavioural intention. Originality/value Although some efforts have been made to identify crisis emotions, the validity of the existing scales have not been affirmed in other crises related to product consumption situations. The results of the present study, thus, made contributions by enhancing an understanding of crisis emotions and their impacts on consumer loyalty intention and WOM communications.

Purpose - Realizing the importance of psychological capital of marketers for their work, the authors aim to investigate the mediating role of quality of work life, job effort, and job attractiveness in the relationship between psychological capital and job performance of marketers in a transitioning market, Vietnam. Design/methodology/approach - To test the mediating role of quality of work life, job effort, and job attractiveness in the relationship between psychological capital and job performance, the authors used a survey data set collected from 696 marketers working for various types of firms in Ho Chi Minh City, Vietnam. Findings - The authors found that psychological capital has both direct and indirect impacts, mediated by quality of work life, job attractiveness, and job effort, on job performance of marketers. Practical implications - The findings suggest that firms should pay attention to psychological capital in their recruiting, training, and development programs. Originality/value - This study documents the mediating role of quality of work life, job effort, and job attractiveness in the relationship between psychological capital and job performance of marketers in a transitioning market, Vietnam.

Purpose Positing that human capital resources of marketers comprise both psychological capital (PsyCap) and marketing capital (MarCap), and that PsyCap in combination with MarCap will have a synergistic effect on marketers’ job performance, the purpose of this paper is to investigate the configurational roles of PsyCap and MarCap in marketers’ job performance. Design/methodology/approach Using a survey data set collected from 472 marketers in Ho Chi Minh City, Vietnam, the study tested the net effects of PsyCap and MarCap on job performance using structural equation modeling (SEM). Then, the study investigated the configurational roles of PsyCap and MarCap in job performance employing the fuzzy-set qualitative comparative analysis (fsQCA). Findings SEM results show that two components of PsyCap (efficacy and optimism) and one component of MarCap (organizational MarCap) have positive effects on job performance. fsQCA findings reveal that, except hope, combinations of PsyCap and MarCap components form several sufficient conditions for job performance. Research limitations/implications The focus of this study is on marketers, that is, at the individual level. Future research should examine both PsyCap and MarCap at a higher level, such as the team, unit, or firm level. Practical implications The study’s findings suggest that firms should pay attention not only to the net effect but also to the configuration of PsyCap and MarCap when designing and implementing their human resource strategies and policies. Originality/value This study contributes to the literature on human capital resources by confirming the configurational roles of PsyCap and MarCap in marketers’ job performance.

Purpose – Realizing the importance of psychological capital of marketers for their work, the authors aim to investigate the mediating role of quality of work life, job effort, and job attractiveness in the relationship between psychological capital and job performance of marketers in a transitioning market, Vietnam. Design/methodology/approach – To test the mediating role of quality of work life, job effort, and job attractiveness in the relationship between psychological capital and job performance, the authors used a survey data set collected from 696 marketers working for various types of firms in Ho Chi Minh City, Vietnam. Findings – The authors found that psychological capital has both direct and indirect impacts, mediated by quality of work life, job attractiveness, and job effort, on job performance of marketers. Practical implications – The findings suggest that firms should pay attention to psychological capital in their recruiting, training, and development programs. Originality/value – This study documents the mediating role of quality of work life, job effort, and job attractiveness in the relationship between psychological capital and job performance of marketers in a transitioning market, Vietnam.

In this study, responses of rice under drought stress correlating with changes in chemical compositions were examined. Among 20 studied rice cultivars, Q8 was the most tolerant, whereas Q2 was the most susceptible to drought. Total phenols, total flavonoids, and antioxidant activities, and their accumulation in water deficit conditions were proportional to drought resistance levels of rice. In detail, total phenols and total flavonoids in Q8 (65.3 mg gallic acid equivalent (GAE) and 37.8 mg rutin equivalent (RE) were significantly higher than Q2 (33.9 mg GAE/g and 27.4 mg RE/g, respectively) in both control and drought stress groups. Similarly, the antioxidant activities including DPPH radical scavenging, β-carotene bleaching, and lipid peroxidation inhibition in Q8 were also higher than in Q2, and markedly increased in drought stress. In general, contents of individual phenolic acids in Q8 were higher than Q2, and they were significantly increased in drought stress to much greater extents than in Q2. However, p-hydroxybenzoic acid was found uniquely in Q8 cultivars. In addition, only vanillic acid was found in water deficit stress in both drought resistant and susceptible rice, suggesting that this phenolic acid, together with p-hydroxybenzoic acid, may play a key role in drought-tolerance mechanisms of rice. The use of vanillic acid and p-hyroxybenzoic acid, and their derivatives, may be useful to protect rice production against water shortage stress.

The relationship between age and seroprevalence can be used to estimate the annual attack rate of an infectious disease. For pathogens with multiple serologically distinct strains, there is a need to describe composite exposure to an antigenically variable group of pathogens. In this study, we assay 24,402 general-population serum samples, collected in Vietnam between 2009 to 2015, for antibodies to eleven human influenza A strains. We report that a principal components decomposition of antibody titer data gives the first principal component as an appropriate surrogate for seroprevalence; this results in annual attack rate estimates of 25.6% (95% CI: 24.1% – 27.1%) for subtype H3 and 16.0% (95% CI: 14.7% – 17.3%) for subtype H1. The remaining principal components separate the strains by serological similarity and associate birth cohorts with their particular influenza histories. Our work shows that dimensionality reduction can be used on human antibody profiles to construct an age-seroprevalence relationship for antigenically variable pathogens. Multi-strain pathogens, such as influenza, present challenges for interpretation of seroprevalence data as estimates may vary by strain. Here, the authors develop a method for estimating age-specific seroprevalence based on principal components analysis and apply it to influenza data from Vietnam.

Phalaenopsis spp. is the most commercially and economically important orchid, but their plant parts are often left unused, which has caused environmental problems. To date, reports on phytochemical analyses were most available on endangered and medicinal orchids. The present study was conducted to determine the total phenolics, total flavonoids, and antioxidant activity of ethanol extracts prepared from leaves and roots of six commercial hybrid Phalaenopsis spp. Leaf extracts of “Chian Xen Queen” contained the highest total phenolics with a value of 11.52 ± 0.43 mg gallic acid equivalent per g dry weight and the highest total flavonoids (4.98 ± 0.27 mg rutin equivalent per g dry weight). The antioxidant activity of root extracts evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay and β-carotene bleaching method was higher than those of the leaf extracts. Eleven phenolic compounds were identified, namely, protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid, syringic acid, vanillin, ferulic acid, sinapic acid, p-coumaric acid, benzoic acid, and ellagic acid. Ferulic, p-coumaric and sinapic acids were concentrated largely in the roots. The results suggested that the root extracts from hybrid Phalaenopsis spp. could be a potential source of natural antioxidants. This study also helps to reduce the amount of this orchid waste in industrial production, as its roots can be exploited for pharmaceutical purposes.

Seroepidemiological studies aim to understand population-level exposure and immunity to infectious diseases. Their results are normally presented as binary outcomes describing the presence or absence of pathogen-specific antibody, despite the fact that many assays measure continuous quantities. A population’s natural distribution of antibody titers to an endemic infectious disease may include information on multiple serological states – naiveté, recent infection, non-recent infection, childhood infection – depending on the disease in question and the acquisition and waning patterns of immunity. In this study, we investigate 20,152 general-population serum samples from southern Vietnam collected between 2009 and 2013 from which we report antibody titers to the influenza virus HA1 protein using a continuous titer measurement from a protein microarray assay. We describe the distributions of antibody titers to subtypes 2009 H1N1 and H3N2. Using a model selection approach to fit mixture distributions, we show that 2009 H1N1 antibody titers fall into four titer subgroups and that H3N2 titers fall into three subgroups. For H1N1, our interpretation is that the two highest-titer subgroups correspond to recent and historical infection, which is consistent with 2009 pandemic attack rates. Similar interpretations are available for H3N2, but right-censoring of titers makes these interpretations difficult to validate.