Impact of damming the Mogi-Guaçu River (São Paulo State, Brazil) on reservoir limnological variables

This study examined the effects of the damming of the Mogi‐Guaçu River (São Paulo State, Brazil) on the surface current velocity, water temperature, Secchi disc transparency, turbidity, colour, conductivity, pH and concentrations of nutrients and pigments. Surface‐water samples were taken before, during and after the reservoir was filled. Three sampling sites were established, one in the upper reach of the reservoir, one in the central area of the reservoir and one downstream from the dam. An additional sampling site was established on the Peixe River, the major tributary of the Mogi‐Guaçu in the study area. After filling of the reservoir, the surface current velocity tended to decrease, excepting downstream of the dam. The pH, and the Kjeldahl nitrogen, ammonia and chlorophyll‐a concentrations, tended to increase. The nitrite concentrations increased mainly in the upper reach and central area of the reservoir. The Secchi disc transparency and colour tended to decrease. A decreasing trend in dissolved oxygen concentration was observed mainly at the central area of reservoir. The conductivity tended to decrease, later returning to levels observed prior to reservoir filling. The nitrate, total phosphorus and orthophosphate concentrations exhibited an increasing trend after reservoir filling, followed by a decreasing concentration, reaching lower levels than those found prior to reservoir filling. High phaeophytin concentrations were measured for the filling phase. The observed water quality changes for Mogi‐Guaçu Reservoir generally were not as extreme as those observed for other tropical reservoirs. This trend was related to the operation of the reservoir. As Mogi‐Guaçu Reservoir is a run‐of‐the‐river reservoir with a short water retention time, the flooded area is not extensive and the retention of material and sedimentation upstream from the dam is not remarkable. These facts explain the small water quality changes observed for most of the variables after reservoir filling. The water quality decreased at the in‐lake site in the central part of the reservoir, attaining a hypereutrophic condition. This fact was related to the ageing of the reservoir and to cultural eutrophication.     

Numerical computation of free meandering channels with the application of slump blocks on the outer bends

Application of slump failure mechanism in the numerical modeling of the free meandering is the recent advancement towards dealing the real phenomena on the outer bends of meandering rivers with the numerical models. Recently numerous numerical simulations are performed using two-dimensional morphodynamic model for bed and bank with consideration of effects of slump blocks. Four different cases are simulated separately for steady and unsteady flow condition for about 6 h with and without slump block consideration. The measured bank erosion, channel migration and the channel width evolution show significant difference in the results due to inclusion of slump block effects. Long term simulation has been performed for 24 h to predict the free meandering behavior with variation of different slump block parameters. The result shows clear bar formation and projection, channel formation and migration towards the outer bends, making longer length of the flow path and increasing the sinuosity with the time which is very similar with the natural rivers.     

Stabilization of effective exchange rates under common currency basket systems

We investigate the extent to which a common currency basket peg would stabilize effective exchange rates of East Asian currencies. We use an AMU (Asian Monetary Unit), which is a weighted average of ASEAN10 plus 3 (Japan, China, and Korea) currencies, as a common currency basket to investigate the stabilization effects. We compare our results with another result on stabilization effects of the common G3 currency (the US dollar, the Japanese yen, and the euro) basket in the East Asian countries [Williamson, J., 2005, A currency basket for East Asia, not just China. In: Policy Briefs in International Economics, No. PB05-1. Institute for International Economics]. We obtained the following results: first, the AMU peg system would be more effective in reducing fluctuations of the effective exchange rates of East Asian currencies as a number of countries applied the AMU peg system increases in East Asia. Second, the AMU peg system would more effectively stabilize the effective exchange rates than a common G3 currency basket peg system for four (Indonesia, the Philippines, South Korea, and Thailand) of the seven countries. The results suggest that the AMU peg system would be useful for the East Asian countries whose trade weights on Japan are relatively higher than others. J. Japanese Int. Economies 20 (4) (2006) 590–611.     

Bubbles,growth and imperfection of credit market in a two-country model

This study extends Hirano and Yanagawa (Rev Econ Stud 84(1):406–443, 2017) to an asymmetric two-country model and examines bubbles effects on each country’s long-run economic growth rate. This study also provides numerical examples with respect to the relationship between each country’s growth rate and their financial frictions in the balanced growth equilibria with bubbles and without bubbles. It shows that foreign bubbles have positive and negative effects on both countries’ growth rates, and which effect dominates depends on the level of financial development in both countries. In this study, the positive effect of bubbles tends to dominate when the total level of financial frictions in both countries is relatively low. When the total effect of bubbles on the growth rate is positive, the burst of foreign bubbles leads to a decrease in the growth rate in both countries. This implies that there is a positive correlation between foreign bubbles and the domestic as well as the foreign country’s growth rate.     

Separating the Age Effect from a Repeat Sales Index: Land and Structure Decomposition

Since real estate is heterogeneous and not all its quality attributes are observable, the repeat sales model pioneered by Bailey et al. (1963) has become one of the standard methods to estimate a constant-quality price index. The model, however, fails to adjust for depreciation, as age and time between sales have an exact linear relationship. This paper proposes a new method to estimate an age-adjusted repeat sales index by decomposing property value into land and structure components. As depreciation is more relevant to the structure than land, the property’s depreciation rate should depend on the relative size of land and structure. The larger the land component, the lower the depreciation rate of the property. This new method is applied to property transactions in Hong Kong and Tokyo. Hong Kong is shown to have a higher depreciation rate based on a fixed structure-to-property value ratio, while the resulting age adjustment is larger in Tokyo because its land value has shrunken over time.     

An Artificial Neural Network Test For Structural Change With Unspecified Parametric Form

Tests for a structural change of unknown timing in parameterized regression functions have been introduced previously under the maintained assumption that the models are correctly specified. However, the existing family of tests are unable to discriminate between structural change and misspecification. This paper introduces test statistics which do not require specification of the parametric form of the underlying data-generating process (DGP). I approximate it by a version of artificial neural networks (ANN). My simulation studies indicate that an ANN approximates the DGP quite well and that the derived tests have good power relative to the power envelope.
JEL Classification Numbers: C12, C14, C45.     

The relationship between pollution abatement costs and environmental regulation: Evidence from the Chinese industrial sector

Since the 2000s, China has been trying to strengthen emission controls in response to increasing pollution problems. However, strict implementation of emission controls generates pollution abatement costs. Using regional data for 29 provinces in the Chinese industrial sector from 1995 to 2010, this study estimated the pollution abatement costs for each province through the measurement of environmental efficiency, by applying a directional distance function approach. Moreover, using panel data analysis, this study clarified whether there is a nonlinear relationship between pollution abatement costs and environmental regulations. The empirical results are as follows. The study confirmed that the burden of abatement costs tended not only to occur in the central and western regions but also to increase in the eastern region. Moreover, the nonlinear relationship is inverted U‐shaped; thus, pollution abatement costs increase, as a negative effect of environmental regulations, until a certain inflection point, after which they decrease.     

Agricultural policy reforms and WTO commitments on domestic support in Japan

The purpose of this paper is to provide a comprehensive review of Japan＇s agricultural domestic policy since 1995 in the context of the current international negotiations in the WTO Doha Round, which has as one aim further reductions of trade-distorting support among member countries. Apparently, Japan＇s attitude towards agricultural domestic policy reform is one of compliance with the WTO, which requests member countries to reduce their Aggregate Measure of Support （AMS） through trimming trade-distorting （amber box） support and/or transforming traditional-type agricultural subsidies to decoupled-type ones. Japan reduced its amber box support by nearly 80 percent between 1995 and 2000. This drastic reduction is mainly attributable to Japan＇s removal of rice from the amber box in 1998. In addition, following the WTO＇s principle of decoupling, Japan launched an extensive agricultural subsidy reform in 2007. This paper, however, shows the ironical realities of Japanese agricultural policy. Neither a sharp reduction of amber box support nor Japan＇s 2007 reform necessarily means there will be a reduction of trade-distorting effects. On the contrary, the 2007 reform may in fact stimulate domestic rice production.     

Distribution of dioxins in surface soils and river-mouth sediments and their relevance to watershed properties.

The dioxins toxic equivalent (TEQ) concentration in surface soils, river sediments and river-mouth sediments was measured by the CALUX assay in the Yasu and Ado River basins around Lake Biwa, Japan. In order to examine the distribution of dioxins in each watershed, we evaluated and compared the correlation between the dioxins TEQ concentration and the solid characteristics (i.e. organic carbon content and particle size distribution) of all samples. In both basins, the dioxins TEQ concentration in forest soil correspondingly showed a very good linear relationship to organic carbon content. On the other hand, the dioxins TEQ concentration in paddy field was significantly high, although organic carbon content was relatively low. Generally, the smaller particles have the higher dioxins TEQ concentrations in surface soils, and river sediments were composed of very coarse particles and had relatively low dioxins TEQ concentration. Therefore, we expected high dioxins TEQ concentration in river-mouth sediment, which was, however, not the case. Although the dioxins TEQ concentration in river-mouth sediments is low, the degree of dioxins pollution was different in each basin. The difference was considered to come from the difference of watershed properties including land use, river-slope, dam construction as well as the surface soil pollution.