Biological responses to environmental forcing: the linear tracking window hypothesis

Determining the relative contributions of intrinsic and extrinsic processes to the regulation of biological populations has been a recurrent ecological issue. Recent discussions concerning ecosystem "regime shifts" again raise the question of whether population fluctuations are mainly controlled by external forcing. Results of nonlinear time series analyses indicate that pelagic populations typically do not passively track stochastic environmental variables. Rather, population dynamics are better described as nonlinear amplification of physical forcing by biological interactions. However, we illustrate that in some cases populations do show linear tracking of the physical environment. To explain why population dynamics can sometimes be linear, we propose the linear tracking window hypothesis: populations are most likely to track the stochastic environmental forcing when their generation time matches the characteristic time scale of the environmental signal. While our observations follow this hypothesis well, our results indicate that the linear tracking window is a necessary but not a sufficient condition.     

A STRATEGY FOR IMPLEMENTING BMPs FOR CONTROLLING NONPOINT SOURCE POLLUTION: THE CASE OF THE FEI‐TSUI RESERVOIR WATERSHED IN TAIWAN1

ABSTRACT: This paper describes a concerted effort by the Taiwan Water Resources Bureau, the City of Taipei, and the Bureau of Fei‐tsui Reservoir Management to protect the water quality in the Fei‐tsui Reservoir.The reservoir is the major source of water supply for over two million people in the metropolitan area of Taipei. Over the years the reservoir has suffered from siltation and more recently eutrophication. The sources of the pollution are traced to the hundreds of tea gardens, rice fields and other agricultural areas in the watershed and to urban sources such as construction sites. Large amounts of nutrients enter the reservoir by way of storm water runoff during storm or typhoon events. Since 1999, various agencies have worked to initiate an effort to reduce nonpoint pollution in the Fei‐Tsui Reservoir watershed. Practices being considered include nonstructural measures such as nutrient management, and structural measures such as swales, detention basins, and wetlands, in addition to erosion and sediment control methods. A number of field tests have been completed on the performance of selected best management practices (BMPs). A strategy for implementing the BMPs at the watershed scale has been developed based on a total maximum daily load (TMDL) analysis that is reported in this paper.     

A study of assessment indicators for environmental sustainable development of science parks in Taiwan

This study adopted the ecological footprint calculation structure to calculate the ecological footprints of the three major science parks in Taiwan from 2008 to 2010. The result shows that the ecological footprints of the Hsinchu Science Park, the Central Taiwan Science Park, and the Southern Taiwan Science Park were about 3.964, 2.970, and 4.165 ha per capita. The ecological footprint (EF) of the Central Taiwan Science Park was the lowest, meaning that the influence of the daily operations in the Central Taiwan Science Park on the environment was rather low. Secondly, the population density was relatively high, and the EF was not the highest of the Hsinchu Science Park, meaning that, while consuming ecological resources, the environmental management done was effective. In addition, the population density in Southern Taiwan Science Park is 82.8 units, lower than that of Hsinchu Science Park, but its ecological footprint per capita is 0.201 units, higher than Hsinchu, implying its indicator management has space for improvement. According to the analysis result above, in the science parks, the percentages of high-energy-consuming industries were rather high. It was necessary to encourage development of green industries with low energy consumption and low pollution through industry transformation.     

Establishment and applied research on environmental sustainability assessment indicators in Taiwan

The study utilizes the method of Material Flow, Ecological Footprint Model and other related indicators to establish the Indicator System of Sustainable Development. Principal Component Analysis is used to abstract the representative factors in order to estimate the indicators of ecological sustainable development during 1998~2005 in Taiwan, as well as to make policy recommendations. The research indicates following results: (1) The Direct Material Input (DMI) of Taiwan shows constant instability and depends on heavy import activity. The annual increase of considerable greenhouse gas emission leads to a comparative growth of the Domestic Process Output (DOP). The both material consumption and inventory formation of the economy are unsteady. In addition, the Physical Trade Balance (PTB) indicates that supply exceeds demand, as well as the occasional shortage of building materials. (2) The 2005 per capita Ecological Demand footprint in Taiwan is 6.5392 hm(2), making the Ecological Deficit per capita 4.8569 hm(2). The figures reflect that productivity and life intensity of residents have exceeded the carrying capacity of Taiwan's ecological economic system. (3) The overall Synthetic Trend Indicators of Sustainable Development in Taiwan are decreasing. Therefore, if proper measures are not adopted in time, the current weak sustainability will lead into the vicious circle which departs from sustainable development.     

Determination and Impact of Volatile Organics Emitted during Rush Hours in the Ambient Air around Gasoline Stations

Abstract

This study analyzes the volatile organic compounds (VOCs) in the ambient air around gasoline stations during rush hours and assesses their impact on human health. Results from this study clearly indicate that methyl tertiary butyl ether (MTBE), toluene, and isobutane are the major VOCs emitted from gasoline stations. Moreover, the concentrations of MTBE and toluene in the ambient air near gasoline stations are remarkably higher than those sampled on surrounding roads, revealing that these compounds are mainly released from gasoline stations. The concentration of VOCs near the gasoline stations without vapor recovery systems are ～7.3 times higher than those around the gasoline stations having the recovery systems. An impact on individual health and air quality because of gasoline station emissions was done using Integrated Risk Information System and Industrial Source Complex Short Term model.     

Lake eutrophication management modeling using dynamic programming

Lake eutrophication problems have received considerable attention in Taiwan, especially because they relate to the quality of drinking water. In this study, steady-state river water quality and lake eutrophication models are solved using dynamic programming algorithms to find the nutrient removal rates for eutrophication control during dry season. The kinetic cycle of chlorophyll-a, phosphorus and nitrogen for a complete-mixed lake is considered in the optimization framework. The Newton-iterative technique is adopted to solve the nonlinear equations for the steady-state lake eutrophication model. The optimization framework is applied to Cheng-Ching Lake in southern Taiwan. Several nutrient loading scenarios for eutrophication control are studied. Optimization results for nutrient removal rates and corresponding wastewater treatment capacities of each reach of the Kao-Ping River define the least cost approach to lake eutrophication control. A natural purification method, structural free water surface wetland, is also suggested to save more investment and improve river water quality at the same time.     

Dry deposition of sulfate-containing particulate at the highway intersection, coastal and suburban areas

Sulfate-containing aerosol (SCA) dry deposition at the highway intersection, coastal location, and suburban area in Taiwan were analyzed and compared. Sampling was accomplished with a surrogate surface technique. Samples particles were coated with barium chloride (BaCl(2)) in a vacuum evaporator and then exposed to a relative humidity of 85% for 2 h to form distinctive products of SCAs. Treated samples were examined by a scanning electron microscopy. SCA dry deposition fluxes were 10.2, 4.1, 3.4 microgm(-2)s(-1) and nonsulfate-containing aerosol (NSCA) dry deposition fluxes were 23.3, 8.2, 13.5 microgm(-2)s(-1) at the highway intersection, coastal, and suburban areas. At the highway intersection, both SCA and NSCA dry deposition fluxes were much higher than those at the other two sites. The dry deposition of particles was also analyzed with a traditional technique. The number median diameters (NMDs) of SCA were 0.41, 0.82, and 1.2 mum at the highway intersection, coastal, and suburban sites, respectively. The highway intersection site had a small NMD, which showed that most sulfate-containing deposited aerosols existed in fine diameter range. The mass median diameters (MMDs) of SCA were 8.8, 19.5, and 14.9 mum at the highway intersection, coastal, and suburban sites, which were much higher than NMDs. Average numbers of SCAs in total particulate were 33%, 33%, and 22% at the highway intersection, coastal and suburban areas Most deposited particulates were nonsulfate-containing at the three sampling sites. SCAs less than 10 mum contributed 29%, 8%, and 7% to the total dry deposition at the highway intersection, coastal, and suburban areas, respectively. The contribution of fine particulate was significantly higher at the highway intersection site.     

The research on extracting the information of human errors in the main control room of nuclear power plants by using Performance Evaluation Matrix

Digitalized nuclear instruments and control systems have been the main stream design for the main control room (MCR) of advanced nuclear power plants (NPPs) nowadays. Digitalization of human–system interface (HSI) could improve human performance and, on the other hand, could reduce operators’ situation awareness as well. It might cause that humans make wrong decision during an emergency unintentionally. Besides, digital HSI relies on computers to integrate system information automatically instead of human operation. It has changed the operator’s role from mainly relating operational activity to mainly relating monitoring. However, if the operators omit or misjudge the information on the video display units and wide display panel, the error of omission and error of commission may occur. This study applies Content Category Analysis (CCA) and Performance Evaluation Matrix (PEM) methods to explore the potential problems in the MCR of advanced NPPs which are caused by human errors. The results show that the potential problems that would probably contribute to the human performance of MCR in the advanced NPPs are multiple accidents, pressure level, number of operators, and other factors such as working environmental. The conclusions of this research may be considered to avoid and prevent human errors in the human factor related researches especially in the nuclear safety field.