Assortment Size and Performance of Online Sellers: An Inverted U-Shaped Relationship

This paper investigates the role of assortment size in sellers’ performance in the e-commerce context, which has been primarily associated with lowered search costs and switching costs. However, in contrast to the findings in the literature, our theoretical analysis postulates an inverted U-shaped association, showing that performance of online sellers increases and then decreases as the assortment size becomes larger. The nonlinear effect can be effectively explained by the interplay between the benefits derived from simultaneous consumer utility and the liabilities derived from the competition-intensifying effect. Additionally, the optimal level of assortment size is reduced when market density or product uncertainty is high. Using a data set of 10,000 online sellers from a large e-commerce platform, our hypotheses concerning the inverted U-shaped curve and moderation effects of market density and product uncertainty are statistically supported. Our research contributes to the assortment literature by revealing the special effects of assortment size in the online retailing context, and provides practical implications for online sellers’ assortment planning and optimization under both general settings and specific conditions

Junction Temperature Consistency Analysis of MMC Submodule

Although modular multilevel converter（MMC）is currently widely used in the field of DC power transmission due to its excellent topology performance, the natural DC bias characteristics inevitably cause thermal imbalance of internal devices. Too high temperature at the junction of power devices is one of the major causes of damage. Therefore, it is necessary to further investigate the factors that affect the device junction temperature. This paper calculated the power loss and junction temperature by combined the thermal impedance model and compared junction temperature under two typical modulation strategies

Intergenerational transmission of education in China: New evidence from the Chinese Cultural Revolution

This paper estimates the effect of parental education on children’s education by using instruments generated by the Chinese Cultural Revolution, and further explores the mechanisms of this causal relationship. Several important findings stand out from our empirical analyses. We find a larger intergenerational persistence in education for higher level in urban areas but for a lower level of education in rural areas. The main results from instrumental variable estimation show that the nurture effect is larger and more significant for fathers than for mothers. A deeper investigation of the mechanism behind this nurture effect informs us that a father’s education passes on to his children’s education partly through the income channel. Another notable finding is that even after controlling for fathers’ income, parental education still has a significantly positive effect on children’s education through the nurture effect. This indicates that beyond the income channel, there may exist other channels such as better home environment, which deserve to be explored in future research.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147763/1/rode12558_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147763/2/rode12558.pd

“GROWTH OF THE FITTER”: EVOLUTIONARY GROWTH PATHS AND FIRM SIZE OF START-UPS IN E-MARKETS

Existing research related to firm growth has not paid sufficient attention to the growth paths of online stores in e-markets. The linkage between growth path and firm size has not been built up. This paper aims to investigate evolutionary trajectories and their effects on firm size. Theoretically, conceptually define three types of distinguishable paths, namely the convergent, tepid, and sustained paths. We then propose related theoretical hypotheses that reflect the impacts of different types of growth paths on the resulting firm size. To empirically validate the proposed hypotheses, we applied the trajectory analysis method with a novel indicator, the relative expansion rate, based on a data set that consists of 5,582 online stores on Taobao.com, the largest e-commerce platform in the world. Testing results largely support our hypotheses and suggest that the sustained growth path is the ideal mode nascent online sellers should struggle for, since it is significantly positively related to the firm size that the sellers can achieve. To achieve their goal of firm expansion, new online sellers should aggressively pursue opportunities in the short term, which is a reflection of the “the growth of the fitter” principle. Our findings also suggest that E-commerce platforms may attempt to facilitate the sustained growth path of sellers through including growth path analysis in the evaluation system of online stores

Weak antilocalization and electron-electron interaction in coupled multiple-channel transport in a Bi2_2Se3_3 thin film

Electron transport properties of a topological insulator Bi$_2$Se$_3$ thin film are studied in Hall-bar geometry. The film with a thickness of 10 nm is grown by van der Waals epitaxy on fluorophlogopite mica and Hall-bar devices are fabricated from the as-grown film directly on the mica substrate. Weak antilocalization and electron-electron interaction effects are observed and analyzed at low temperatures. The phase-coherence length extracted from the measured weak antilocalization characteristics shows a strong power-law increase with decreasing temperature and the transport in the film is shown to occur via coupled multiple (topological surface and bulk states) channels. The conductivity of the film shows a logarithmically decrease with decreasing temperature and thus the electron-electron interaction plays a dominant role in quantum corrections to the conductivity of the film at low temperatures.Comment: 12 pages, 5 figure

Clinical efficacy and safety of Kanglaite injection, adjuvant cemcitabine and cisplatin chemotherapy for advanced non-small-cell lung cancer: A systematic review and meta-analysis

Purpose: To investigate the effectiveness and safety of the combination of Kanglaite injection (KLTi) and gemcitabine and cisplatin (GP) chemotherapy in the treatment of advanced non-small cell lung cancer (NSCLC).Methods: PubMed, Web of Science, Embase, Cochrane Library, CNKI, Wan-Fang, CBM, and CQVIP were comprehensively searched from January 2010 till November 2020. Randomized controlled trials (RCTs) of KLTi plus GP in the treatment of NSCLC were selected and assessed for inclusion. Review Manager 5.3 software was used for meta-analysis.Results: Twenty-five RCTs on advanced NSCLC examined the inclusion criteria. The meta-analysis showed that compared with GP chemotherapy alone, KLTi plus GP chemotherapy significantly improved objective response rate (ORR) (RR = 1.36, 95% CI 1.23-1.51, p < 0.00001), disease control rate (DCR) (RR = 1.17, 95% CI 1.11 - 1.23, p < 0.00001), and reduced adverse drug reactions(ADRs) such as hair loss (RR = 0.60, 95% CI 0.47 - 0.76, p < 0.0001), gastrointestinal reaction (RR = 0.68, 95% CI 0.62 - 0.75, p < 0.00001), impairment of liver and kidney function (RR = 0.65, 95% CI 0.53 - 0.80, p < 0.001), nervous system damage (RR = 0.42, 95% CI 0.26 - 0.69, p = 0.0005), myelosuppression (I-II phase) (RR = 0.79, 95 % CI 0.66 - 0.95, p = 0.01), myelosuppression (III-IV phase) (RR = 0.44, 95 % CI0.27 - 0.72, p = 0.001), anemia (RR = 0.74, 95 % CI 0.60 - 0.91, p = 0.006), leukopenia (RR = 0.78, 95% CI 0.69, 0.87, p < 0.0001), thrombocytopenia (RR = 0.59, 95 % CI 0.49, 0.72, p < 0.00001), hypochromia (RR = 0.74, 95% CI 0.59, 0.92, p = 0.008).Conclusion: KLTi adjuvant GP chemotherapy reduces adverse effects in patients with advanced NSCLC. Thus, KLTi might be an effective and safe intervention for NSCLC&nbsp

Microbial metabolites are involved in tumorigenesis and development by regulating immune responses

The human microbiota is symbiotic with the host and can create a variety of metabolites. Under normal conditions, microbial metabolites can regulate host immune function and eliminate abnormal cells in a timely manner. However, when metabolite production is abnormal, the host immune system might be unable to identify and get rid of tumor cells at the early stage of carcinogenesis, which results in tumor development. The mechanisms by which intestinal microbial metabolites, including short-chain fatty acids (SCFAs), microbial tryptophan catabolites (MTCs), polyamines (PAs), hydrogen sulfide, and secondary bile acids, are involved in tumorigenesis and development by regulating immune responses are summarized in this review. SCFAs and MTCs can prevent cancer by altering the expression of enzymes and epigenetic modifications in both immune cells and intestinal epithelial cells. MTCs can also stimulate immune cell receptors to inhibit the growth and metastasis of the host cancer. SCFAs, MTCs, bacterial hydrogen sulfide and secondary bile acids can control mucosal immunity to influence the occurrence and growth of tumors. Additionally, SCFAs, MTCs, PAs and bacterial hydrogen sulfide can also affect the anti-tumor immune response in tumor therapy by regulating the function of immune cells. Microbial metabolites have a good application prospect in the clinical diagnosis and treatment of tumors, and our review provides a good basis for related research

Mapping Functional Brain Activation Using [14C]-Iodoantipyrine in Male Serotonin Transporter Knockout Mice

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