A New Method for Measuring Tail Exponents of Firm Size Distributions

The authors propose a new method for estimating the power-law exponents of firm size variables. Their focus is on how to empirically identify a range in which a firm size variable follows a power-law distribution. On the one hand, as is well known a firm size variable follows a power-law distribution only beyond some threshold. On the other hand, in almost all empirical exercises, the right end part of a distribution deviates from a power-law due to finite size effects. The authors modify the method proposed by Malevergne et al. (2011). In this way they can identify both the lower and the upper thresholds and then estimate the power-law exponent using observations only in the range defined by the two thresholds. They apply this new method to various firm size variables, including annual sales, the number of workers, and tangible fixed assets for firms in more than thirty countries.This special issue follows the "First Unconventional Workshop on Quantitative Finance and Economics" held at the International Christian University in Tokyo the 21st–23th of February 2011, but is open also to contributions not presented in it

The Mechanism of Water Cycle System in Lake Inba-Numa Watershed:A Comparative Study of Runoff Mechanisms of Small Watersheds

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Removal of Anhydrite and Mg-Silicate Scales from Production Wells Using Chemical Agents at the Mori Geothermal Field in Hokkaido, Japan: An Application of Chemical Well Stimulation

ABSTRACT Well stimulation, which enhances permeability, is an important technique in the creation of Engineered Geothermal Systems (EGS). In addition to physical stimulation such as hydrofracturing, chemical stimulation has been used at several EGS fields. In addition to conventional mineral acids, chelating agents and alkaline solutions have been studied and employed to dissolve calcium and silica minerals without significant casing corrosion. We tested the notion that this chemical stimulation technique was applicable to the removal of anhydrite and Mg-silicate deposits as a replacement for costly mechanical workovers. We conducted two scale removal operations using chelating and alkaline agents at the Mori geothermal field. Two distinct scale minerals, anhydrite and Mg-silicate, were observed in two different production wells. The latter scale consists of crystalline and amorphous structures. We confirmed that the chelating and alkaline solutions not only dissolved anhydrite and Mg-silicate scales but caused them to spall into particles and powders in the laboratory prior to the stimulation on site. The spalled scale fragments can be readily ejected from the wellbore during production. We injected a chelating agent and alkaline solutions into the wells in July and November, 2008. Combined with successive production, the majority of scale was removed and the treated wells showed improved productivity

The novel heart-specific RING finger protein 207 is involved in energy metabolism in cardiomyocytes

A failing heart shows severe energy insufficiency, and it is presumed that this energy shortage plays a critical role in the development of cardiac dysfunction. However, little is known about the mechanisms that cause energy metabolic alterations in the failing heart. Here, we show that the novel RING-finger protein 207 (RNF207), which is specifically expressed in the heart, plays a role in cardiac energy metabolism. Depletion of RNF207 in neonatal rat cardiomyocytes (NRCs) leads to a reduced cellular concentration of adenosine triphosphate (ATP) and mitochondrial dysfunction. Consistent with this result, we observed here that the expression of RNF207 was significantly reduced in mice with common cardiac diseases including heart failure. Intriguingly, proteomic approaches revealed that RNF207 interacts with the voltage-dependent anion channel (VDAC), which is considered to be a key regulator of mitochondria function, as an RNF207-interacting protein. Our findings indicate that RNF207 is involved in ATP production by cardiomyocytes, suggesting that RNF207 plays an important role in the development of heart failure

Clinical Statistics for Dysphagia Patients ≦ 18 Years of Age in the Center of Special Needs Dentistry, April 2012-March 2013

In April 2012, the Center of Special Needs Dentistry (SND) was established at Showa University Dental Hospital to provide function training for children with eating and swallowing disorders. A statistical clinical assessment was performed on new patients ≤18 years of age who visited the Center over a 1-year period (April 2012–March 2013) to assess the conditions present at the initial visit. In all, 60 patients (29 boys, 31 girls, mean (± SD) age 4.2±4.1 years, range 0-18 years of age) were included in the study. Most patients were <1 year of age (32%) and most came from one of four cities in the Johnan area (Shinagawa City, Meguro City, Ota City and Setagaya City). The most common primary diseases at the initial visit were cerebral palsy and cleft lip and palate. The third largest patient group was of healthy children with oral function problem. Over 60% of patients attended the Center of SND because of an eating-related complaint. More than 50% of patients were obtaining nutrients via oral intake; the remaining patients were obtaining nutrients via non-oral or a combination of oral and non-oral intake. Because of the young age of the patients and the fact that most were from neighboring areas, it can be inferred that effective community health care is being provided. It is necessary for the Center of SND to continue to provide professional treatment for dysphagia and to contribute to community medicine

JSPS Grants-in-Aid for Creative Scientific Research Emergence of power laws with different power-law exponents from reversal quasi-symmetry and Gibrat&apos;s law Emergence of power laws with different power-law exponents from reversal quasi-symmetry and Gibrat

Abstract. To explore the emergence of power laws in social and economic phenomena, the authors discuss the mechanism whereby reversal quasi-symmetry and Gibrat&apos;s law lead to power laws with different powerlaw exponents. Reversal quasi-symmetry is invariance under the exchange of variables in the joint PDF (probability density function). Gibrat&apos;s law means that the conditional PDF of the exchange rate of variables does not depend on the initial value. By employing empirical worldwide data for firm size, from categories such as plant assets K, the number of employees L, and sales Y in the same year, reversal quasi-symmetry, Gibrat&apos;s laws, and power-law distributions were observed. We note that relations between power-law exponents and the parameter of reversal quasi-symmetry in the same year were first confirmed. Reversal quasi-symmetry not only of two variables but also of three variables was considered. The authors claim the following. There is a plane in 3-dimensional space (log K, log L, log Y ) with respect to which the joint PDF PJ (K, L, Y ) is invariant under the exchange of variables. The plane accurately fits empirical data (K, L, Y ) that follow power-law distributions. This plane is known as the Cobb-Douglas production function, Y = AK α L β which is frequently hypothesized in economics

A New Method for Measuring Tail Exponents of Firm Size Distributions

The authors propose a new method for estimating the power-law exponents of firm size variables. Their focus is on how to empirically identify a range in which a firm size variable follows a power-law distribution. On the one hand, as is well known a firm size variable follows a power-law distribution only beyond some threshold. On the other hand, in almost all empirical exercises, the right end part of a distribution deviates from a power-law due to finite size effects. The authors modify the method proposed by Malevergne et al. (2011). In this way they can identify both the lower and the upper thresholds and then estimate the power-law exponent using observations only in the range defined by the two thresholds. They apply this new method to various firm size variables, including annual sales, the number of workers, and tangible fixed assets for firms in more than thirty countries

The Emergence of Different Tail Exponents in the Distributions of Firm Size Variables

We discuss a mechanism through which inversion symmetry (i.e., invariance of a joint probability density function under the exchange of variables) and Gibrat's law generate power-law distributions with different tail exponents. Using a dataset of firm size variables, that is, tangible fixed assets K, the number of workers L, and sales Y, we confirm that these variables have power-law tails with different exponents, and that inversion symmetry and Gibrat's law hold. Based on these findings, we argue that there exists a plane in the three dimensional space (log K, log L, log Y), with respect to which the joint probability density function for the three variables is invariant under the exchange of variables. We provide empirical evidence suggesting that this plane fits the data well, and argue that the plane can be interpreted as the Cobb-Douglas production function, which has been extensively used in various areas of economics since it was first introduced almost a century ago.2012～2016年度科学研究費補助金[基盤研究(S)]「長期デフレの解明」(研究代表者 東京大学経済学研究科・渡辺努, 課題番号：24223003

The Emergence of Different Tail Exponents in the Distributions of Firm Size Variables

We discuss a mechanism through which inversion symmetry (i.e., invariance of a joint probability density function under the exchange of variables) and Gibrat\u27s law generate power-law distributions with different tail exponents. Using a dataset of firm size variables, that is, tangible fixed assets K, the number of workers L, and sales Y, we confirm that these variables have power-law tails with different exponents, and that inversion symmetry and Gibrat\u27s law hold. Based on these findings, we argue that there exists a plane in the three dimensional space (log K, log L, log Y), with respect to which the joint probability density function for the three variables is invariant under the exchange of variables. We provide empirical evidence suggesting that this plane fits the data well, and argue that the plane can be interpreted as the Cobb-Douglas production function, which has been extensively used in various areas of economics since it was first introduced almost a century ago.2012～2016年度科学研究費補助金[基盤研究(S)]「長期デフレの解明」(研究代表者 東京大学経済学研究科・渡辺努, 課題番号：24223003

Firm Growth Function and Extended-Gibrat’s Property

We analytically show that the logarithmic average sales of firms first follow power-law growth and subsequently follow exponential growth, if the growth-rate distributions of the sales obey the extended-Gibrat’s property and Gibrat’s law. Here, the extended-Gibrat’s property and Gibrat’s law are statistically observed in short-term data, which denote the dependence of the growth-rate distributions on the initial values. In the derivation, we analytically show that the parameter of the extended-Gibrat’s property is identical to the power-law growth exponent and that it also decides the parameter of the exponential growth. By employing around one million bits of exhaustive sales data of Japanese firms in the ORBIS database, we confirmed our analytic results