Monitoring of human enteric viruses and coliform bacteria in waters after urban flood in Jakarta, Indonesia.

Floodwaters in Kampung Melayu village, Jakarta, Indonesia, as well as river water and consumable water (including groundwater and tap water) samples in flooded and non-flooded areas, were quantitatively analysed to assess occurrence of viruses and total coliforms and E. coli as bacterial indicators after flooding event. High numbers of enterovirus, hepatitis A virus, norovirus (G1, G2) and adenovirus were detected at high concentration in floodwaters and waters sampled from Ciliwung River which runs across metropolitan Jakarta and is used widely for agriculture and domestic purposes by poor residents. One out of three groundwater wells in the flooded area was contaminated with all viruses tested while no viruses were found in groundwater samples in non-flooded areas and tap water samples. The results revealed that human enteric viruses, especially hepatitis A virus and adenovirus, were prevalent in Jakarta, Indonesia. This study suggested that flooding posed a higher risk of viral infection to the people through contamination of drinking water sources or direct contact with floodwaters.     

Effects of soil erosion on water quality and water uses in the upper Phong watershed.

The main objective of this paper is to simulate the effects of soil erosion on river water quality and on agricultural production as a result of the transformation of forestlands in the catchment of the upstream Phong River. Suspended solids carry down attached nutrients and agricultural chemicals causing water pollution in the downstream. There are four different types of land use in this simulation, namely forestlands, flatland and highland sugarcane plantation areas, and paddy fields. The highest mean annual amount of soil erosion is from paddy fields (585,700 tons/year), followed by highland (73,800 tons/year) and flatland (63,950 tons/year) sugarcane plantation areas and forestlands (41,800 tons/year), respectively. However, as most of paddy fields are located in a low land and are wet type cultivations, the soil erosion occurred has less impact on river water quality and its production compared to the soil erosion from the steeper slopes of highland plantation areas. Under the resource-based agriculture, the sugarcane production is mainly increased by expanding the plantation areas leading to a significant loss of topsoil and a considerable reduction of agricultural production. Soil erosion contributes to an increase in the average annual suspended solids concentration by 72 mg/l.     

Sources and leaching of manganese and iron in the Saigon River Basin, Vietnam

High concentrations of manganese and iron in the Saigon River are major problems for the water supply in Ho Chi Minh City (HCMC), Viet Nam. To identify their sources and leaching processes, we surveyed water quality along the Saigon River and ran batch leaching tests using soil and sediment samples. Two important leaching processes were identified: acidic leaching from acid sulfate soil (ASS) in the middle reaches of the river, and Mn dissolution and Fe reduction from sediments in the downstream reaches. Low pH caused the concurrent release of Fe and Mn from the ASS. In contrast, anoxia caused the release of Fe but not Mn from the sediments, whereas low pH facilitated Mn dissolution. Sediments are a more important source of Mn because of their higher Mn contents (10 times) and release rates (14 times) than those from ASS.     

Morphological characteristics of flood refugia of cobble-bed vegetation

Periodic flooding alters riverine vegetation community composition; moderate flood disturbance maintains communities at an early seral stage, whereas severe floods may remove entire communities. After disturbance, plants may recolonize riverbeds from refugia.Here, we investigated the morphological characteristics of refugia where riverine plants survived large floods. At three sites, plant communities growing on cobble-bars were surveyed, and the hydraulic characteristics of each site were analyzed. The populations of an indicator plant, Anaphalis margaritacea sub-species yedoensis (Franch. et Savat.) were assessed after major floods in 2004 and 2009. At each survey, the particle size and bed composition were measured, and the critical shear-stress required to move particles at each site was calculated. A one-dimensional flow and the average and local shear-stress at ten different discharges, including that of the largest flood were calculated. The results demonstrate that the A. margaritacea community is maintained at locations where the local shear-stress at peak discharge in large-floods does not exceed a critical value. These conditions were achieved in locations with particular morphological characteristics, where the river is not constrained by levees and is restricted by a downstream narrow-pass; in this reach river width increases with discharge thus limiting the increase in water depth with increasing discharge and allowing the establishment of refugia where plant species may survive large floods.Flooding and reestablishment from refugia maintain a characteristic riverbed community in equilibrium.     

Welfare gain from quality and price development in the Japan’s LCD TV market

We estimate the welfare gain from innovations in the LCD TVs that prevailed during the period 2005–2007 in Japan, via consumer surplus that we measure with the aid of discrete choice methods, using market data obtained from an internet price comparison service (Kakaku.com). Further, by the measured implicit values of attributes, we evaluate in monetary terms, the qualitative transition embedded in the attributes through the iso-consumer surplus planes. We thereby disaggregate the welfare gain into the qualitative and the budgetary components, which we call the quality gain, and the budget gain, respectively. The estimates show, along with the evolved process of innovation, that the quality gain was in the order of 381 KJPY, while the budget gain was 94 KJPY negative, which gives about 287 KJPY of overall welfare gain per consumer, during the period.     

Did Japan's shopping coupon program increase spending?

In March 1999, 31 million “shopping coupons” worth 20,000 yen each were distributed to Japanese families with children and to the elderly. The coupons expired after six months and could only be used within the recipient's local community. We use variation in the number of children across families and in the number of recipients across prefectures to measure the effect of the coupons on spending. We find that coupons had a positive effect on spending on semi-durables, but no effect on spending on nondurables or services. The marginal propensity to consume on semi-durables was 0.1–0.2 when the coupons were distributed in March. The results using regional variation provide stronger evidence that spending did not fall after the coupons had been redeemed.     

The influence of indoor air on personal exposure to volatile organic compounds and its risk estimation

This paper summarizes the results of personal exposure monitoring and estimates the risk from exposure to 18 volatile organic compounds compared with health criteria set by the US Environmental Protection Agency. In study 1, personal exposure levels and outdoor air concentrations were compared, and in study 2, personal exposure levels and the corresponding indoor air concentrations were compared. From these studies, it was concluded that personal exposure to volatile organic compounds depended markedly on indoor air quality and that handling of compounds increased personal exposure markedly. Risk estimations indicated that chloroform in tap water, benzene from cigarette smoke and p -dichlorobenzene from household insecticide needed caution.     

A Comprehensive Approach for Estimating Hydraulic Quantities in a Multi-branched Estuarine System

Despite many previous investigations, there is no theoretically justifiable equation to determine the freshwater discharge, tidal velocity, and salinity in a complex estuary that contains several branches. In this study, the longitudinal distributions of freshwater and salinity concentration in multi-branched estuaries are investigated using a mathematical model, considering the energy balance by frictional head loss and the salt balance by diffusion and advection in a one-dimensional steady-state condition. We attempt to obtain the time-mean freshwater discharge rate quantitatively at a junction where the main flow separates into two branches. The salinity distribution along each branch is calculated by following the dispersion coefficient equation previously proposed for a single estuary. The salinity field is divided into the near-coast region and the upstream region, because in each segment the inland velocity varies according to the tidal flux. For computing the tidal velocity, we propose the Burgers equation and the Hoph-Cole transformation. The theoretical results obtained by these equations were found to be in good agreement with a set of observed data in the Red River estuary system.     

Estimating International Interindustry Linkages: Non-survey Simulations of the Asian-Pacific Economy

This paper evaluates a recently published semi-survey international input–output table for nine East-Asian countries and the USA with four non-survey estimation alternatives. A new generalized RAS procedure is used with stepwise increasing information from both import and export statistics as optimisation constraints on the four non-survey tables. The results show that the estimated table improves when increasing information from both sources is used, despite the well known inconsistencies between import and export data in trade statistics. It is concluded that the new procedure can be useful as a critical analysis of newly published (semi-)survey international tables and/or as an early updating tool during the construction process.     

Analytical Solutions for Expected Loss and Standard Deviation of Loss with an Additional Loan

We evaluate the expected loss and the standard deviation of loss of a bank loan, considering the bank’s strategic control of the expected return on the loan. Assuming that the bank supplies an additional loan to minimize the expected loss of the total loan, we provide analytical formulations for the expected loss and the variance of loss with bivariate normal distribution functions. Using a given expected growth rate and interest rates, two thresholds for the asset/liability ratio can specify three cases. The bank supplies an additional loan to decrease the expected loss in two cases: (i) the asset/liability ratio of the firm is low, and its expected growth rate is high; and (ii) the asset/liability ratio of the firm is high, and the lending interest rate is high. The bank maintains the current loan amount when the asset/liability ratio lies between the two thresholds. Depending on the bank’s strategy, the bank can decrease the initial expected loss of the loan. Conversely, the bank would face a greater risk of the standard deviation of loss.