High-Frequency Heating Extraction Method for Sensitive Drug Analysis in Human Nails

ArticleMolecules. 23(12): 3231(2018)journal articl

Borrowing constraints and protracted recessions

This paper shows that some of the puzzling observations in the protracted recessions of the 1990s in Japan and the 1930s in the United States can be accounted for by a simple variant of the neoclassical growth model with borrowing constraints. There are three puzzles: First, a large wedge emerged between the marginal rate of substitution between consumption and leisure and the marginal product of labor. This labor wedge is associated with declines in labor inputs. Second, although shrinkage of investment was observed in both episodes, a wedge that represents investment frictions did not emerge. Third, in spite of unprecedented monetary easing in Japan since the late 1990s, deflation has continued. A key ingredient is the emergence of a huge accumulation of nonperforming debts, which must have been a consequence of the large fluctuations in asset prices. The debts tighten the borrowing constraints and can cause the puzzling features of the recessions, which may be protracted if the bad debt problem persists for years.

Business Cycle Accounting for the Japanese Economy

We conducted business cycle accounting (BCA) using the method developed by Chari, Kehoe, and McGrattan (2002a) on data from the 1980s--1990s in Japan and from the interwar period in Japan and the United States. The contribution of this paper is twofold. First, we find that labor wedges may have been a major contributor to the decade-long recession in the 1990s in Japan. We argue that the deterioration of the labor wedge may have been caused by sticky wages and monetary contraction, and it may have been prolonged by the continuation of asset-price declines through binding collateral constraints. Second, we performed an alternative BCA exercise using the capital wedge instead of the investment wedge to check the robustness of BCA implications for financial frictions. The accounting results with the capital wedge imply that financial frictions may have had a large depressive effect during the 1930s in the United States. This implication is the opposite of that from the original BCA findings.

"Irrational exuberance" in the Pigou cycle under collateral constraints

The boom-bust cycles such as the episode of the "Internet bubble" in the late 1990s may be described as the business cycle driven by changes in expectations, which is called the Pigou cycle by Beaudry and Portier (An exploration into Pigou's theory of cycles, Journal of Monetary Economics, 2004). The key feature of the notion of the Pigou cycle is the comovements in the consumption, the labor, and the investment, in response to changes in expectations. We show that with the assumption that firms are subject to the collateral constraint in financing labor input (and investment), a fairly standard neoclassical model can generate the Pigou cycle. We also show that the collateral-constraint model with the private information can generate the "irrational exuberance," i.e., a boom in which each firm correctly anticipates that its own productivity will not rise, while it also believes wrongly that the productivity of the other firms will rise dramatically.

Gauge Coupling Sum Rule as a Unification Barometer

Article信州大学理学部紀要 35(2): 55-67(2001)departmental bulletin pape

Debt-Ridden Equilibria - A Simple Theory of Great Depressions -

The US Great Depression and Japan's lost decade in the 1990s are both characterized as persistent stagnations of economies with debt-ridden corporate sectors subsequent to asset-price collapses. We propose a simple model, in which increases in corporate debt (and/or fluctuations in expectations about the future state of the economy) can account for these episodes. Key ingredients are the assumptions that firms are subject to collateral constraint on liquidity for financing the inputs, and that the firms can hold other firms' stocks as their assets and use them as the collateral. Collateral constraint on inputs interlinks the financial market inefficiency with the factor market inefficiencies; and that the corporate stocks are used as collateral generates an externality of self-reference in stock prices and production, that is, higher stock prices loosen the collateral constraint and lead to higher efficiencies in production, which in turn justify the higher stock prices. It is shown that there exists a continuum of steady-state equilibria indexed by the amount of debt that the firms owe to the consumers: A steady state with a larger debt can be called a debt-ridden equilibrium, since it has more inefficient factor markets, produces less output, and is characterized by lower stock prices. The model provides the policy implication that debt reduction in the corporate sector at the expense of consumers (or taxpayers) may be welfare-improving when the firms are debt-ridden.

Collateral Constraint and News-driven Cycles

The boom-bust cycles such as the episode of the "Internet bubble" in the late 1990s may be described as the business cycle driven by changes in expectations or news about the future. The comovements in consumption, labor, and investment, in response to news about productivity changes in the future can be called the news-driven cycles. We show that with the assumption that firms are subject to the collateral constraint in financing input costs, a fairly standard Real Business Cycle model can generate the news-driven cycles. The collateral constraint models have several virtues: (1) The model structure is simple; (2) introduction of the intermediate input enables our models to reproduce procyclical movements in the total factor productivity; (3) our models can generate procyclical movements in price of capital (Tobin's q); and (4) the second model in our paper, which is a modified version of the Carlstrom-Fuerst model, can generate countercyclical movements in bankruptcies, while the original Carlstrom-Fuerst model cannot.

Expression and localization of forkhead transcriptional factor 2 (Foxl2) in the gonads of protogynous wrasse, Halichoeres trimaculatus

<p>Abstract</p> <p>Background</p> <p>Three-spot wrasse, <it>Halichoeres trimaculatus</it>, is a marine protogynous hermaphrodite fish. Individuals mature either as initial phase (IP) males or females. Appropriate social cues induce the sex change from IP female to terminal phase (TP) male. However, the molecular mechanisms behind such a sex change remain largely unknown. Recently, the forkhead transcription factor 2 (Foxl2) was identified as an essential regulator of vertebrate ovarian development/function/phenotype. Inspired by this information, we characterized the expression patterns of Foxl2 in the protogynous wrasse assuming Foxl2 as the female-specific marker in this species.</p> <p>Methods</p> <p>First, we clonedFoxl2 cDNA from ovary by reverse transcription polymerase chain reaction (RT-PCR) followed by rapid amplification of cDNA ends (RACE). Next, we analysed expression pattern of Foxl2 messenger RNA (mRNA) and protein in gonads of different sexual phases by real time quantitative PCR assay and flour fluorescence immunohistochemical method, respectively. Additionally, we studied the changes in Foxl2 expression pattern during aromatase inhibitor (AI)-induced sex change.</p> <p>Results</p> <p>The amino acid sequence (306 AA) of wrasse Foxl2, especially the forkhead domain, shows high identity with that of other reported teleost Foxl2s. Quite unexpectedly, no sexual dimorphism was observable between the testes and ovary in the expression pattern of Foxl2. In female phase fish, signals for Foxl2 protein were detectable in the granulosa cells, but not the theca cells. Transcript levels of Foxl2 in the testes of IP and TP males were identical to that in the ovaries of females and, further, Foxl2 protein was found to be localized in the interstitial cells including tubules and Leydig cells. Treatment with AI induced sex change in male gonads and an up-regulation was seen in the expression of Foxl2 in these gonads.</p> <p>Conclusions</p> <p>Unlike in other vertebrates, including teleosts, Foxl2 may have a different role in the naturally sex changing fishes.</p