Exploring the unknown requires leveraging uncertainty: Two Essays on A Real Options Perspective on the Pattern and Decision-Making of Entrepreneurial Internationalization

Uncertainty is at the center of both entrepreneurship and international business research. One of the fundamental underlying assumptions of entrepreneurship and internationalization theories is that entrepreneurial organizations and entrepreneurs constantly operate in uncertain environments. Even more so in a cross-border context, increasing levels of host country uncertainty can drastically reshape firms’ entrepreneurial internationalization patterns and outcomes as well as entrepreneurs’ internationalization decision making process. Yet, the field of entrepreneurship and international business still lack theoretical explanations for the role of uncertainty in entrepreneurial internationalization. In this two essay dissertation, I applied real options theory, a theoretical perspective that emphasizes decision making at high levels of uncertainty as well as taking advantage of changing levels of uncertainty over time to achieve better organizational outcomes, to re-conceptualize the role of uncertainty in entrepreneurial firms’ internationalization process and entrepreneurs’ internationalization decision making. In Essay one, I compare Transaction Cost Economics (TCE) view with Real Options Theory (ROT) in predicting entrepreneurial firms’ internationalization patterns and outcomes. In particular, by merging several international trade and FDI databases, I empirically tested the impact of host country institutional and economic uncertainty on entrepreneurial firms’ choice of real options entry as well as the effect of real options entry on firms’ entry time, entry location, market exits, and post entry performance. In Essay two, I investigate the uncertainty conditions under which individual entrepreneurs apply real options reasoning in their internationalization decision making process. I theorize the uncertainty leveraging perspective by applying real option reasoning to entrepreneurs’ internationalization decision making. Empirically, I employed a 2 by 2 randomized between and within-subjects mixed design experiment on a representative sample of U.S. international entrepreneurs. Toking together, the two essays examine the role of uncertainty in entrepreneurial internationalization process and decision making. The dissertation contributes to both the entrepreneurship and internationalization literature by offering a real options perspective of uncertainty leveraging and by empirically testing the effects of both perceived and actual host country uncertainty in entrepreneurial firms’ internationalization process and entrepreneurs’ internationalization decision making

Experimental measurement of dynamic concentration of nanofluid in laminar flow

Nanofluid is thought to have a potential enhancement in heat transfer behaviour of fluid. The nanoparticle concentration in nanofluid is one of the most important factors that affect the nanofluid behaviour. The static concentration was applied in the researches under flowing condition. In this paper, Nuclear Magnetic Resonance (NMR) scanning was applied to study the dynamic concentration of nanofluid flow in pipe. The experiments were carried out with ferrofluid under different concentration and temperature. A new parameter T2* was introduced in the study. Experiments were carried out to obtain the T2* of nanofluid in the pipe. An empirical equation based on T2* and temperature was proposed to calculate the concentration of nanoparticles. Then, experiments were carried out with flowing ferrofluid in pipe. The dynamic concentration was calculated with the empirical equation. It has a highest concentration near the pipe wall. The concentration decreases from the wall to the pipe centre. Furthermore, the experiment result also gives out a chance to investigate the mechanism of nanoparticle movement in laminar flow with the concentration gradient along radius

Effect of adding copper oxide nanoparticles on the mass/heat transfer in falling film absorption

Absorber is an essential component that affects the efficiency of absorption refrigeration unit. Falling film absorption is one of the most widespread forms of the heat/mass transfer in absorption system. In this paper, based on the software COMSOL Multiphysics, the finite element method is used to establish the model of falling film absorption. The falling film absorption properties of nanofluids was studied by adding CuO nanoparticles. The results reveal that as the film flow rate increases, the average mass transfer flux rises first and then decreases. The average mass transfer flux increases with the rise of the concentration of solution at the inlet, the decrease of the temperature of solution at the inlet and the reduction of cooling water inlet temperature. After adding copper oxide nanoparticles to lithium bromide solution, the vapor absorption performance of lithium bromide solution can be significantly improved

Targeted learning in observational studies with multi-valued treatments: An evaluation of antipsychotic drug treatment safety

We investigate estimation of causal effects of multiple competing (multi-valued) treatments in the absence of randomization. Our work is motivated by an intention-to-treat study of the relative cardiometabolic risk of assignment to one of six commonly prescribed antipsychotic drugs in a cohort of nearly 39,000 adults with serious mental illnesses. Doubly-robust estimators, such as targeted minimum loss-based estimation (TMLE), require correct specification of either the treatment model or outcome model to ensure consistent estimation; however, common TMLE implementations estimate treatment probabilities using multiple binomial regressions rather than multinomial regression. We implement a TMLE estimator that uses multinomial treatment assignment and ensemble machine learning to estimate average treatment effects. Our multinomial implementation improves coverage, but does not necessarily reduce bias, relative to the binomial implementation in simulation experiments with varying treatment propensity overlap and event rates. Evaluating the causal effects of the antipsychotics on three-year diabetes risk or death, we find a safety benefit of moving from a second-generation drug considered among the safest of the second-generation drugs to an infrequently prescribed first-generation drug known for having low cardiometabolic risk

Bionic inspired study of heat pipe from plant water migration

Heat pipe is well regarded as super thermal conductor and has a wide range of applications in the variety of industry sections. A great number of researches have been done on enhancing the performance of heat pipe through improving the flow pattern. The research on plant water migration based on bionic engineering approach provides a very interesting path to the fluid flow enhancement inside heat pipe, and improvement of inner structure as well. The main forces that drive the water migrates in plants are capillary effect, friction, gravity and transpiration effect, and which are also the main driven forces in heat pipe. Although most researches on heat pipe focus on capillary effect against gravity, transpiration effect is still very important as dragging force occurs when water evaporates. And all these can be investigated through plant water migration. A mathematical model describing the water migration process in plant is proposed in this paper. And the result obtained from mathematical calculation is compared with the experimental measured result using Nuclear Magnetic Resonance (NMR) technology. The perfect matching between the two results confirmed the possibility of using the mathematical model to analyze fluid flow in micro channels, including heat pipe. And it also successfully put transpiration effect and friction into consideration, which give out a clearer view of the forces inside heat pipe for further research

Three-dimensional self-assembling nanofiber matrix rejuvenates aged/degenerative human tendon stem/progenitor cells

The poor healing capacity of tendons is known to worsen in the elderly. During tendon aging and degeneration, endogenous human tendon stem/progenitor cells (hTSPCs) experience profound pathological changes. Here, we explored a rejuvenation strategy for hTSPCs derived from aged/degenerated Achilles tendons (A-TSPCs) by providing three-dimensional (3D) nanofiber hydrogels and comparing them to young/healthy TSPCs (Y-TSPCs). RADA peptide hydrogel has a self-assembling ability, forms a nanofibrous 3D niche and can be further functionalized by adding RGD motifs. Cell survival, apoptosis, and proliferation assays demonstrated that RADA and RADA/RGD hydrogels support A-TSPCs in a comparable manner to Y-TSPCs. Moreover, they rejuvenated ATSPCs to a phenotype similar to that of Y-TSPCs, as evidenced by restored cell morphology and cytoskeletal architecture. Transmission electron, confocal laser scanning and atomic force microscopies demonstrated comparable ultrastructure, surface roughness and elastic modulus of A- and Y-TSPC-loaded hydrogels. Lastly, quantitative PCR revealed similar expression profiles, as well a significant upregulation of genes related to tenogenesis and multipotency. Taken together, the RADA-based hydrogels exert a rejuvenating effect by recapitulating in vitro specific features of the natural microenvironment of human TSPCs, which strongly indicates their potential to direct cell behaviour and overcome the challenge of cell aging and degeneration in tendon repair.D.D. acknowledges the EU Twinning Grant Achilles (H2020- WIDESPREAD-05-2017-Twinning Grant Nr. 810850). H.Y. thanks for the support of China Scholarship Council (CSC Grant Nr. 201606200072). S.K. and H.C-S. acknowledge the financial support for CANTER by the Bavarian State Ministry for Science and Education. The authors thank Daniela Drenkard for valuable technical assistance and Dr. Girish Pattappa for English proof-readin

Dufulin Activates HrBP1 to Produce Antiviral Responses in Tobacco

BACKGROUND: Dufulin is a new antiviral agent that is highly effective against plant viruses and acts by activating systemic acquired resistance (SAR) in plants. In recent years, it has been used widely to prevent and control tobacco and rice viral diseases in China. However, its targets and mechanism of action are still poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: Here, differential in-gel electrophoresis (DIGE) and classical two-dimensional electrophoresis (2-DE) techniques were combined with mass spectrometry (MS) to identify the target of Dufulin. More than 40 proteins were found to be differentially expressed (≥1.5 fold or ≤1.5 fold) upon Dufulin treatment in Nicotiana tabacum K(326). Based on annotations in the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, these proteins were found to be related to disease resistance. Directed acyclic graph (DAG) analysis of the various pathways demonstrated harpin binding protein-1 (HrBP1) as the target of action of Dufulin. Additionally, western blotting, semi-quantitative reverse transcription polymerase chain reaction (RT-PCR), and real time PCR analyses were also conducted to identify the specific mechanism of action of Dufulin. Our results show that activation of HrBP1 triggers the salicylic acid (SA) signaling pathway and thereby produces antiviral responses in the plant host. A protective assay based on lesion counting further confirmed the antiviral activity of Dufulin. CONCLUSION: This study identified HrBP1 as a target protein of Dufulin and that Dufulin can activate the SA signaling pathway to induce host plants to generate antiviral responses

Mathematical and experimental investigation of water migration in plant xylem

Plant can take water from soil up to several metres high. However, the mechanism of how water rises against gravity is still controversially discussed despite a few mechanisms have been proposed. Also, there still lacks of a critical transportation model because of the diversity and complex xylem structure of plants. This paper mainly focuses on the water transport process within xylem and a mathematical model is presented. With a simplified micro channel from xylem structure and the calculation using the model of water migration in xylem, this paper identified the relationship between various forces and water migration velocity. The velocity of water migration within the plant stem is considered as detail as possible using all major forces involved, and a full mathematical model is proposed to calculate and predict the velocity of water migration in plants. Using details of a specific plant, the velocity of water migration in the plant can be calculated, and then compared to the experimental result from Magnetic Resonance Imaging (MRI). The two results match perfectly to each other, indicating the accuracy of the mathematical model, thus the mathematical model should have brighter future in further applications

Fixed‐time stability of stochastic nonlinear systems and its application into stochastic multi‐agent systems

Abstract The paper devotes to study fixed‐time stability of stochastic nonlinear systems and fixed‐time consensus of stochastic multi‐agent systems (SMASs). Firstly, a new fixed‐time stability theorem is established and a high‐precise estimation of settling time is provided. Secondly, as an application, the fixed‐time consensus problem of SMASs is discussed in virtue of the established theorem. A new class of fixed‐time nonlinear consensus protocols with stochastic perturbation is designed by employing the neighbour's information. Based on graph theory, matrix theory and fixed‐time stability theorem, we prove that fixed‐time consensus of SMASs is achieved under the designed protocol. Moreover, some sufficient conditions are proposed to guarantee fixed‐time consensus of SMAS. It is shown that the settling time is not only independent of the initial conditions, but also it has higher precise. In the end, three numerical examples are provided to illustrate correctness of our theoretical results