A Merton Model of Credit Risk with Jumps

In this note, we consider a Merton model for default risk, where the firm’s value is driven by a Brownian motion and a compound Poisson process

The effect of financial and economic growth on tourism development in emerging economies: a study of Vietnam for the interval 1990-2020.

Purpose: The primary study objective is to determine the interaction between economic, financial, and tourism development in Vietnam for the 1990-2020 intervals. Design:This study is conducted through a combination of qualitative and quantitative methods using secondary data from WorldBank, Ourworldindata, and the Vietnam Bureau of Statistics. Methodology: The ARDL model is a statistically more robust approach for cointegration testing; then the ECM model was used to test for short-term effects and finally the Granger test for causality between the observed variables. Findings: Investigating the vital internal force that promotes tourism development reveals that finance and economic growth are crucially crucial during the 31-year study period. To illustrate, the economic and financial contribution to the positive change of tourism is up to 30.4% and 18.1%, respectively. Excitedly, the Granger test demonstrates a one-way causal relationship between economic growth and tourism development, tourism development, and finance development, and finance development and economic growth. In other words, it is a circle that demonstrates a consistently positive impact from tourism development to finance development, from finance development to economic growth, and finally, from economic growth to tourism development. The originality of the research: This paper highlights the role and impact level of the economic and financial sector on the tourism industry of a new Asian tiger and can be considered as the first study on Vietnam. The findings investigate how the economy functioned in the past and support policymakers in establishing future development policies, particularly in post-pandemic recovery

Subtype diversification and synaptic specificity of stem cell-derived spinal inhibitory interneurons

During nervous system development, thousands of distinct neuronal cell types are generated and assembled into highly precise circuits. The proper wiring of these circuits requires that developing neurons recognize their appropriate synaptic partners. Analysis of a vertebrate spinal circuit that controls motor behavior reveals distinct synaptic connections of two types of inhibitory interneurons, a ventral V1 class that synapses with motor neurons and a dorsal dI4 class that selectively synapses with proprioceptive sensory neuron terminals that are located on or in close proximity to motor neurons. What are the molecular and cellular programs that instruct this remarkable synaptic specificity? Are only subsets of these interneurons capable of integrating into this circuit, or do all neurons within the same class behave similarly? The ability to answer such questions, however, is hampered both by the complexity of the spinal cord, where many different neuronal cell types can be found synapsing in the same area; as well as by the challenge of obtaining enough neurons of a particular subtype for analysis. Meanwhile, pluripotent stem cells have emerged as powerful tools for studying neural development, particularly because they can be differentiated to produce large amounts of diverse neuronal populations. Mouse embryonic stem cell-derived neurons can thus be used in a simplified in vitro system to study the development of specific neuronal cell types as well the interactions between defined cell types in a controlled environment. Using stem cell-derived neurons, I investigated how the V1 and dI4 cardinal spinal classes differentiate into molecularly distinct subtypes and acquire cell type-specific functional properties, including synaptic connectivity. In Chapter Two, I describe the production of lineage-based reporter stem cell lines and optimized differentiation protocols for generating V1 and dI4 INs from mouse embryonic stem cells, including confirming that they have molecular and functional characteristics of their in vivo counterparts. In Chapter Three, I show that a well-known V1 interneuron subtype, the Renshaw cell, which mediates recurrent inhibition of motor neurons, can be efficiently generated from stem cell differentiation. Importantly, manipulation of the Notch signaling pathway in V1 progenitors impinges on V1 subtype differentiation and greatly enhances the generation of Renshaw cells. I further show that sustained retinoic acid signaling is critical for the specific development of the Renshaw cell subtype, suggesting that interneuron progenitor domain diversification may also be regulated by spatially-restricted cues during embryonic development. In Chapter Four, using a series of transplantation, rabies virus-based transsynaptic tracing, and optogenetics combined with whole-cell patch-clamp recording approaches, I demonstrate that stem cell-derived Renshaw cells exhibit significant differences in physiology and connectivity compared to other V1 subpopulations, suggesting that synaptic specificity of the Renshaw cell-motor neuron circuit can be modeled and studied in a simplified in vitro co-culture preparation. Finally, in Chapter Five, I describe ongoing investigations into molecular mechanisms of dI4 interneuron subtype diversification, as well as approaches to studying their synaptic specificity with proprioceptive sensory neurons. Overall, my results suggest that our stem cell-cell based system is well-positioned to probe the functional diversity of molecularly-defined cell types. This work represents a novel use of embryonic stem cell-derived neurons for studying inhibitory spinal circuit assembly and will contribute to further understanding of neural circuit formation and function during normal development and potentially in diseased states

The Effect of Entrepreneurial Attitudes and Individual Attributes on Entrepreneurial Activity in the context of ASEAN Member States: Evidence from Thailand and Vietnam

This study analyzes the influence of entrepreneurial attitudes and individual at­tributes on entrepreneurial activity in two ASEAN member countries: Vietnam and Thai­land. By applying the multinomial logistics regression (MLR) analysis method, the results show that those with an entrepreneurial network, who can read business opportunities, and have skills and knowledge, have a positive and significant influence when deciding to start and invest in others’ new businesses. On the other hand, females and those with a secondary education were more likely to engage in entrepreneurial activities. The study also shows that Vietnam’s entrepreneurial attitudes and individual characteristics seem to be better, differentiating it from Thailand. The Global Entrepreneurship Monitor (GEM) data from 2017 were the most recent data available at the time of this study. However, the availability of more up-to-date data is considered necessary to enrich and expand the im­pact of future research

Space-time domain decomposition for advection-diffusion problems in mixed formulations

This paper is concerned with the numerical solution of porous-media flow and transport problems , i. e. heterogeneous, advection-diffusion problems. Its aim is to investigate numerical schemes for these problems in which different time steps can be used in different parts of the domain. Global-in-time, non-overlapping domain-decomposition methods are coupled with operator splitting making possible the different treatment of the advection and diffusion terms. Two domain-decomposition methods are considered: one uses the time-dependent Steklov--Poincar{\'e} operator and the other uses optimized Schwarz waveform relaxation (OSWR) based on Robin transmission conditions. For each method, a mixed formulation of an interface problem on the space-time interface is derived, and different time grids are employed to adapt to different time scales in the subdomains. A generalized Neumann-Neumann preconditioner is proposed for the first method. To illustrate the two methods numerical results for two-dimensional problems with strong heterogeneities are presented. These include both academic problems and more realistic prototypes for simulations for the underground storage of nuclear waste