Endogenous Borrowing Constraints and Wealth Inequality

This paper studies the evolution of wealth inequality in an economy with endogenous borrowing constraints. In the model economy, young agents need to borrow to finance human capital investments but cannot commit to repaying their loans. Creditors can punish defaulters by banishing them permanently from the credit market. At equilibrium, loan default is prevented by imposing a borrowing limit tied to the borrower\u27s inheritance. The heterogeneity in inheritances translates into heterogeneity in borrowing limits: endogenously, some borrowers face a zero borrowing limit, and some are partly constrained, whereas others are unconstrained. Depending on the initial distribution of inheritances, it is possible that all lineages are attracted either to the zero-borrowing-limit steady state or to the unconstrained-borrowing steady state—long-run equality. It is also possible that some lineages end up in one steady state and the rest in the other—complete polarization

Endogenous borrowing constraints and wealth inequality

This paper studies the evolution of wealth inequality in an economy with endogenous borrowing constraints. In the model economy, agents need to borrow to finance human capital investments but cannot commit to repaying their loans. Creditors can punish defaulters by banishing them permanently from the credit market. In equilibrium, loan default is prevented by imposing a borrowing limit tied to the borrower\u27s inheritance. The heterogeneity in inheritances translates into heterogeneity in the borrowing limits: endogenously, some young borrowers face a zero borrowing limit, some are partly constrained, while others are unconstrained. Depending on the initial distribution of inheritances, it is possible all lineages are attracted to either the zero-borrowing-limit steady state or to the unconstrained-borrowing steady state -- long-run equality. It is also possible some lineages end up at one steady state and the rest at the other -- complete polarization. Interestingly, the wealth dynamics in the model closely resemble that in the seminal work of Galor and Zeira (1993)

Fabrication of a microresonator-fiber assembly maintaining a high-quality factor by CO2 laser welding

We demonstrate fabrication of a microtoroid resonator of a high-quality (high-Q) factor using femtosecond laser three-dimensional (3D) micromachining. A fiber taper is reliably assembled to the microtoroid using CO2 laser welding. Specifically, we achieve a high Q-factor of 2.12*10^6 in the microresonator-fiber assembly by optimizing the contact position between the fiber taper and the microtoroid.Comment: 7 pages, 5 figure

On-chip electro-optic tuning of a lithium niobate microresonator with integrated in-plane microelectrodes

We demonstrate electro-optic tuning of an on-chip lithium niobate microresonator with integrated in-plane microelectrodes. First two metallic microelectrodes on the substrate were formed via femtosecond laser process. Then a high-Q lithium niobate microresonator located between the microelectrodes was fabricated by femtosecond laser direct writing accompanied by focused ion beam milling. Due to the efficient structure designing, high electro-optical tuning coefficient of 3.41 pm/V was observed.Comment: 6 pages, 3 figure

Time-Sensitive Collaborative Filtering Algorithm with Feature Stability

In the recommendation system, the collaborative filtering algorithm is widely used. However, there are lots of problems which need to be solved in recommendation field, such as low precision, the long tail of items. In this paper, we design an algorithm called FSTS for solving the low precision and the long tail. We adopt stability variables and time-sensitive factors to solve the problem of user's interest drift, and improve the accuracy of prediction. Experiments show that, compared with Item-CF, the precision, the recall, the coverage and the popularity have been significantly improved by FSTS algorithm. At the same time, it can mine long tail items and alleviate the phenomenon of the long tail

Anti-arthritic effect of total anthraquinone from Polygonum cuspidatum on type II collagen-induced arthritis in rats

Purpose: To study the anti-arthritic effect of total anthraquinone from Polygonum  cuspidatum (TAPC) on type II collagen-induced arthritis (CIA) in rats, and to  investigate the underlying mechanism(s).Methods: CIA rats were prepared and treated orally with TAPC at doses of 50, 100 and 200 mg/kg/day, for 24 days. Paw volume and arthritis score were measured prior to TAPC treatment, and subsequently at 3-day intervals on days 3, 6, 9, 12, 15, 18, 21 and 24. Serum levels of TNF-α, IL-6 and IL-17 were determined by enzyme-linked immunosorbent assay (ELISA), while synovial tissue TNF-α, IL-6 and IL-17mRNA expressions were assayed by real time-polymerase chain reaction (RT-PCR). Thymus and spleen indices were also determined.Results: TAPC (50, 100 and 200 mg/kg) significantly alleviated paw swelling (p < 0.05), arthritis scores (p < 0.05) and thymus and spleen indices (p < 0.05) of CIA rats, when compared with the control rats. In addition, TAPC significantly decreased serum levels of the pro-inflammatory cytokines TNF-α, IL-6 and IL-17 (p < 0.01); and down-regulated their mRNA expressions in synovial tissues (p < 0.01).Conclusion: These results suggest that TAPC exerts good anti-arthritic activity in rats, most probably via suppression of inflammatory responses.Keywords: Polygonum cuspidatum, Anthraquinone, Type II collagen-induced  arthritis, Pro-inflammatory cytokine

Arctic Ocean Amplification in a warming climate in CMIP6 models

Arctic near-surface air temperature warms much faster than the global average, a phenomenon known as Arctic Amplification. The change of the underlying Arctic Ocean could influence climate through its interaction with sea ice, atmosphere, and the global ocean, but it is less well understood. Here, we show that the upper 2000 m of the Arctic Ocean warms at 2.3 times the global mean rate within this depth range averaged over the 21st century in the Coupled Model Intercomparison Project Phase 6 Shared Socioeconomic Pathway 585 scenario. We call this phenomenon the “Arctic Ocean Amplification.” The amplified Arctic Ocean warming can be attributed to a substantial increase in poleward ocean heat transport, which will continue outweighing sea surface heat loss in the future. Arctic Amplification of both the atmosphere and ocean indicates that the Arctic as a whole is one of Earth’s regions most susceptible to climate change

Recombinant porcine rotavirus VP4 and VP4-LTB expressed in Lactobacillus casei induced mucosal and systemic antibody responses in mice

<p>Abstract</p> <p>Background</p> <p>Porcine rotavirus infection is a significant cause of morbidity and mortality in the swine industry necessitating the development of effective vaccines for the prevention of infection. Immune responses associated with protection are primarily mucosal in nature and induction of mucosal immunity is important for preventing porcine rotavirus infection.</p> <p>Results</p> <p><it>Lactobacillus casei </it>expressing the major protective antigen VP4 of porcine rotavirus (pPG612.1-VP4) or VP4-LTB (heat-labile toxin B subunit from <it>Echerichia coli</it>) (pPG612.1-VP4-LTB) fusion protein was used to immunize mice orally. The expression of recombinant pPG612.1-VP4 and pPG612.1-VP4-LTB was confirmed by SDS-PAGE and Western blot analysis and surface-displayed expression on <it>L. casei </it>was verified by immunofluorescence. Mice orally immunized with recombinant protein-expressing <it>L. casei </it>produced high levels of serum immunoglobulin G (IgG) and mucosal IgA. The IgA titters from mice immunized with pPG612.1-VP4-LTB were higher than titters from pPG612.1-VP4-immunized mice. The induced antibodies demonstrated neutralizing effects on RV infection.</p> <p>Conclusion</p> <p>These results demonstrated that VP4 administered in the context of an <it>L. casei </it>expression system is an effective method for stimulating mucosal immunity and that LTB served to further stimulate mucosal immunity suggesting that this strategy can be adapted for use in pigs.</p