Mitigating information frictions in trade:Evidence from export credit guarantees

Information frictions make foreign trade risky. In particular, the risk of buyer default deters firms from selling abroad. To address this issue, many countries offer export credit guarantees to provide insurance to exporters. In this paper, we investigate the causal effects of guarantees by exploiting a quasi-natural experiment in Sweden and rich register data on guarantees, firms and trade. Estimates from a fuzzy regression discontinuity design show large positive effects on the probability of exporting and the value of exports to the destination for which the guarantees are issued. These results are robust to an alternative approach using a difference-in-differences matching estimator. Further findings suggest that guarantees impact firms heterogeneously and play an important role in resolving buyer default risk and easing liquidity constraints. Larger impacts are observed in non-OECD countries, on smaller, liquidity constrained exporters and for firms selling products that face a relatively high cost of buyer default.</p

Leukotriene B4 receptor knockdown affects PI3K/AKT/mTOR signaling and apoptotic responses in colorectal cancer

Colorectal cancer (CRC) presents a landscape of intricate molecular dynamics. In this study, we focused on the role of the leukotriene B4 receptor (LTB4R) in CRC, exploring its significance in the disease's progression and potential therapeutic approaches. Using bioinformatics analysis of the GSE164191 and the Cancer Genome Atlas-colorectal adenocarcinoma (TCGA-COAD) datasets, we identified LTB4R as a hub gene influencing CRC prognosis. Subsequently, we examined the relationship between LTB4R expression, apoptosis, and the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway through cellular and mice experiments. Our findings revealed that LTB4R is highly expressed in CRC samples and is pivotal for determining prognosis. In vitro experiments demonstrated that silencing LTB4R significantly impeded CRC cell viability, migration, invasion, and colony formation. Correspondingly, in vivo tests indicated that LTB4R knockdown led to markedly slower tumor growth in mice models. Further in-depth investigation revealed that LTB4R knockdown significantly amplified the apoptosis in CRC cells and upregulated the expression of apoptosis-related proteins, such as caspase-3 and caspase-9, while diminishing p53 expression. Interestingly, silencing LTB4R also resulted in a significant downregulation of the PI3K/AKT/mTOR signaling pathway. Moreover, pretreatment with the PI3K activator 740Y-P only partially attenuated the effects of LTB4R knockdown on CRC cell behavior, emphasizing LTB4R's dominant influence in CRC cell dynamics and signaling pathways. LTB4R stands out as a critical factor in CRC progression, profoundly affecting cellular behavior, apoptotic responses, and the PI3K/AKT/mTOR signaling pathway. These findings not only shed light on LTB4R's role in CRC but also establish it as a potential diagnostic biomarker and a promising target for therapeutic intervention

Impact of hospital bed shortages on the containment of COVID-19 in Wuhan

The global outbreak of COVID-19 has caused worrying concern amongst the public and health authorities. The first and foremost problem that many countries face during the outbreak is a shortage of medical resources. In order to investigate the impact of a shortage of hospital beds on the COVID-19 outbreak, we formulated a piecewise smooth model for describing the limitation of hospital beds. We parameterized the model while using data on the cumulative numbers of confirmed cases, recovered cases, and deaths inWuhan city from 10 January to 12 April 2020. The results showed that, even with strong prevention and control measures in Wuhan, slowing down the supply rate, reducing the maximum capacity, and delaying the supply time of hospital beds all aggravated the outbreak severity by magnifying the cumulative numbers of confirmed cases and deaths, lengthening the end time of the pandemic, enlarging the value of the effective reproduction number during the outbreak, and postponing the time when the threshold value was reduced to 1. Our results demonstrated that establishment of the Huoshenshan, Leishenshan, and Fangcang shelter hospitals avoided 22,786 people from being infected and saved 6524 lives. Furthermore, the intervention of supplying hospital beds avoided infections in 362,360 people and saved the lives of 274,591 persons. This confirmed that the quick establishment of the Huoshenshan, Leishenshan Hospitals, and Fangcang shelter hospitals, and the designation of other hospitals for COVID-19 patients played important roles in containing the outbreak in Wuhan

Transcriptome Analysis of H2O2-Treated Wheat Seedlings Reveals a H2O2-Responsive Fatty Acid Desaturase Gene Participating in Powdery Mildew Resistance

Hydrogen peroxide (H2O2) plays important roles in plant biotic and abiotic stress responses. However, the effect of H2O2 stress on the bread wheat transcriptome is still lacking. To investigate the cellular and metabolic responses triggered by H2O2, we performed an mRNA tag analysis of wheat seedlings under 10 mM H2O2 treatment for 6 hour in one powdery mildew (PM) resistant (PmA) and two susceptible (Cha and Han) lines. In total, 6,156, 6,875 and 3,276 transcripts were found to be differentially expressed in PmA, Han and Cha respectively. Among them, 260 genes exhibited consistent expression patterns in all three wheat lines and may represent a subset of basal H2O2 responsive genes that were associated with cell defense, signal transduction, photosynthesis, carbohydrate metabolism, lipid metabolism, redox homeostasis, and transport. Among genes specific to PmA, ‘transport’ activity was significantly enriched in Gene Ontology analysis. MapMan classification showed that, while both up- and down- regulations were observed for auxin, abscisic acid, and brassinolides signaling genes, the jasmonic acid and ethylene signaling pathway genes were all up-regulated, suggesting H2O2-enhanced JA/Et functions in PmA. To further study whether any of these genes were involved in wheat PM response, 19 H2O2-responsive putative defense related genes were assayed in wheat seedlings infected with Blumeria graminis f. sp. tritici (Bgt). Eight of these genes were found to be co-regulated by H2O2 and Bgt, among which a fatty acid desaturase gene TaFAD was then confirmed by virus induced gene silencing (VIGS) to be required for the PM resistance. Together, our data presents the first global picture of the wheat transcriptome under H2O2 stress and uncovers potential links between H2O2 and Bgt responses, hence providing important candidate genes for the PM resistance in wheat

Does Gibrat’s Law hold for Swedish energy firms?

Gibrat's law predicts that firm growth is purely random and should be independent of firm size. We use a random effects-random coefficient model to test whether Gibrat's law holds on average in the studied sample as well as at the individual firm level in the Swedish energy market. No study has yet investigated whether Gibrat's law holds for individual firms, previous studies having instead estimated whether the law holds on average in the samples studied. The present results support the claim that Gibrat's law is more likely to be rejected ex ante when an entire firm population is considered, but more likely to be confirmed ex post after market selection has "cleaned" the original population of firms or when the analysis treats more disaggregated data. From a theoretical perspective, the results are consistent with models based on passive and active learning, indicating a steady state in the firm expansion process and that Gibrat's law is violated in the short term but holds in the long term once firms have reached a steady state. These results indicate that approximately 70 % of firms in the Swedish energy sector are in steady state, with only random fluctuations in size around that level over the 15 studied years

Firm dynamics and competition in the electricity market

This thesis consists of four independent essays that deal with the firm dynamics and competition in the electricity market. Specifically, it addresses two important facets of firm dynamics, namely, firm performance (growth and profitability) and the change in competition intensity that Swedish electricity firms face, brought by the process of deregulation in Swedish electricity market. Essay 1 investigates whether Gibrat’s law holds for individual firms. The results support the claim that Gibrat’s law is more likely to be rejected ex ante when an entire firm population is considered, but more likely to be confirmed ex post after market selection has “cleaned” the original population of firms or when the analysis treats more disaggregated data. Essay 2 examines the determinants of firm growth in the Swedish electricity sector. The results indicate that large firms do not grow faster than do other firms in the sector, and that electricity firms’ internal resources are indeed the key determinants of firm growth in the Swedish electricity industry. Essay 3 shows that although multi-plant firms are more prevalent than single-plants firms in industries characterized by scale economies and imperfect competition, multi-plant electricity firms on average have a one percentage-point lower return on total asset than their single-plant counterparts as they reach a ‘steady state’ firm size when an optimal size is identified. The potential reasons could be loss of control across hierarchical levels within multi-plant firms or the adaption to technological changes lag behind in comparison to single–plant firms. Essay 4 compare competition intensity before and after the launch of Internet electricity price comparison sites (IEPCS). The heterogeneous effects on competition intensity are found, with the largest effect on competition found in parts of the market that were already characterized by high levels of competition before the launch of IEPCS

Stayin' Alive : Export Credit Guarantees and Export Survival

We use survival analysis to analyse the impact of export credit guarantees on firms’ export duration using granular Swedish panel data at the firm-country and firm-country-product levels. The estimation results show that firms’ export survival substantially increases with guarantees, at both levels. The associations are particu- larly strong for smaller firms and contracts as well as in trade with riskier markets. The findings have implications for policies to promote long-run export growth.Insatser för utrikeshandelns finanserin

Stayin' Alive : Export Credit Guarantees and Export Survival

We use survival analysis to analyse the impact of export credit guarantees on firms’ export duration using granular Swedish panel data at the firm-country and firm-country-product levels. The estimation results show that firms’ export survival substantially increases with guarantees, at both levels. The associations are particu- larly strong for smaller firms and contracts as well as in trade with riskier markets. The findings have implications for policies to promote long-run export growth.Insatser för utrikeshandelns finanserin