The major aim of this thesis project was to determine the variables that most explain the elevated mercury concentrations in lake trout (<i>Salvelinus namaycush</i>), a predatory aquatic fish species in some lakes in northwestern Canada. High mercury concentrations in lake trout in other regions have been associated with the biological features of the fish and various chemical and physical aspects of their aquatic ecosystems. Data including lake trout age, length, weight, and stable isotope values, water chemistry, latitude, and lake and watershed area were collected, compiled and then included in statistical analyses of the factors affecting mercury concentration in the muscle of lake trout from a series of lakes from the Mackenzie River Basin (MRB) in the Northwest Territories (NT), Canada. These results are reported in Chapter 2. Fish age and lake surface area were the most important variables affecting mercury concentrations. However mercury concentration in muscle also was significantly (p < 0.05) related to: fish length, weight, and δ13C; watershed area to lake area ratio; and to total mercury concentration in zooplankton and water. These variables were run through best subsets analyses and multiple regressions in order to determine the regression equation most efficiently capable of predicting mercury concentration in lake trout in unstudied lakes in the MRB region. The resulting equation was: log Hg = 0.698 (0.0156 × latitude) + (0.0031 × age) + (0.000535 × length) (0.245 × log lake area) + (0.00675 × watershed area/lake area ratio), r2 = 0.73<p>Small lakes located in the southern NT and dominated by large and/or old lake trout are most likely to have lake trout whose mean mercury concentrations exceed 0.5 μg/g; the guideline for the commercial sale of fish. Latitude may be linked to mean annual temperature (and variables such as duration of ice cover, summer water temperature) while fish age and length may be related in part to fishing pressures and growth rates on these lake populations. In chapter 3, a more in-depth study was undertaken to investigate of role of feeding and relative tropic level in the bioaccumulation of mercury in lake trout. This was accomplished by comparing MRB lake trout population characteristics with those from a series of lakes in northern Alberta and Saskatchewan (NAS). The two population groups were compared with respect to size, age, growth rates, and mercury concentrations. In addition, trophic and mercury biomagnification relationships, as inferred from stable carbon and nitrogen isotope analyses, for the two lake trout populations were compared. Lake trout from the NT exhibited significantly higher mercury concentrations than those from the NAS lakes (p < 0.001). Mercury concentrations in biota (including lake trout, forage fish, benthic invertebrates and zooplankton) were positively and significantly correlated to δ15N values in all lakes in both of the study areas (p < 0.001). Mercury biomagnification in the NT lakes, as estimated from the slope of δ15N versus mercury concentration, was lower than in the NAS lakes. Thus, mercury biomagnifies more slowly in NT lake trout, but because of their greater mean age, reaches higher values than in NAS lakes. Northwest Territory lake trout generally exhibited more negative δ13C values, indicating more pelagic feeding habits than in NAS lakes: higher mercury concentrations previously have been associated with more pelagic feeding. <p>Finally, the relationship between mercury levels and growth rates in lake trout was investigated by comparing NAS and NT lake trout populations. These results are reported in chapter 4. Lake trout from the NT lakes grew at a slower rate (10.4 mm per year) than those from the NAS lakes (35.1 mm per year). Log mercury concentration was inversely correlated (p < 0.001) with growth rate for both lake trout populations; however, growth rate explained more of the variation in mercury level in the NT lakes than in the NAS lakes (NT, r2 = 0.11, p < 0.001; NAS, r2 = 0.03, p = 0.024). However, the correlation between mercury concentration and growth rate in the NAS study area improved when Reindeer Lake, possibly affected by anthropogenic inputs, was removed from the analyses (r = 0.13, p = 0.001). Therefore, lower mercury levels in lake trout are associated with higher growth rates through growth dilution. The higher mercury concentrations in NT lake trout are due not only to the old age of the fish, but to slower growth rates as well.

Abstract The thesis is addressing the inventory valuation method called moving average and how this inventory method handles exchange rate differences. Intentions of the study is also to highlight differences and similarities between the two methods standard cost and moving average. This study fills an existing gap in science regarding pros and cons with the moving average method which made the topic very interesting.  It also has strong practical contribution regarding possible benefits and problems of relevance to companies that have intentions of implementing moving average on their inventory. The relationships between foreign exchange rate risks and inventory leads to the formulated research question for this thesis: What are the effects of currency movements in the cost of goods sold from an inventory valued at moving average method? Based on the technical problem statement was a constructive approach and interpretive standpoint considered best suited for the study. The gathering of data was conducted by using a qualitative research strategy. Three different topics are used in the theoretical frame; inventory valuation, exchange rates and hedging. The theoretical frame describes the accounting standards behind inventory valuation and exchange rates, as well as the theories addressed. Third and final topic hedging is about how to manage exchange rate exposures using different hedging techniques. The in-depth investigation was made for four business units with inventories valued according to the moving average method. Sampling was divided into two parts one for the companies and another choosing respondents. Selection of companies was a convenient sample within the non-probability samples used and the respondents were selected using a snowball sample. Semi-structured interviews were conducted with nine respondents. Both the empirical- and analysis chapter follows the same three topics as the theory structure and the empirical answers are divided into companies to facilitate the comparison. A short summary of the analysis is that moving average is most suitable for inventories with; high inventory turnovers, sales from shelf and stable costs. There is a need to identify input costs to manage exchange rate differences correctly. The final part about hedging showed that different exposures need different hedging techniques. Forward contracts were the most common financial instrument used for hedging transaction exposures. Input risks also identified as an economic risk is one of the hardest to manage. This study has showed that effects from exchange rate fluctuations affect the moving average inventory value different than other inventory models. The input currencies need to be identified and separated from the sales currencies otherwise there is a potential risk to make wrong decisions.

According to statistics by the Council of Taiwan, the fertility rate in Taiwan is the world's lowest in 2010. The average number of babies born to women of childbearing age life is 0.9 people. In other words, the average number of children per woman is less than 1. In 2023 Taiwan will enter a negative population growth. Taiwan's population structure becomes a declining birthrate, aging society.The future workforce reduction will greatly affect the competitiveness of Taiwan. The most important factor of decreasing fertility in Taiwan is economics.The majority of people think that raising children has become a heavy burden.Except for a few women, due to personal career planning, work and other factors not yet fertility or infertility .The majority of women still want to have her own children.The most people's attitude of giving birth is reserved because of high unemployment rate ,unsound preschool education system and little child-care subsidy . In the empirical study found that there is no relationship between the fertility rates and the amount of maternity allowance.That is maternity grant can not increase fertility rate. If maternity benefits can not be improved the fertility rate,the fertility incentives of tax breaks are smaller to people.There are some shortcomings of tax incentives for increase the birth,such as revenue loss,tax fairness and so on. It is also possible to increase the birth rate had no significant improvement. The government uses tax benefits to increase fertility rate depending on revenue loss and population growth . The amount and range of tax incentives should be calculated carefully in order to make a balance between the revenue loss and population growth.

This dissertation consists of three essays. Chapter II examines the possible asymmetric response of gasoline prices to crude oil price changes using an error correction model with GARCH errors. Recent papers have looked at this issue. Some of these papers estimate a form of error correction model, but none of them accounts for autoregressive heteroskedasticity in estimation and testing for asymmetry and none of them takes the response of crude oil price into consideration. We find that time-varying volatility of gasoline price disturbances is an important feature of the data, and when we allow for asymmetric GARCH errors and investigate the system wide impulse response function, we find evidence of asymmetric adjustment to crude oil price changes in weekly retail gasoline prices Chapter III discusses the relationship between fiscal deficit and exchange rate. Economic theory predicts that fiscal deficits can significantly affect real exchange rate movements, but existing empirical evidence reports only a weak impact of fiscal deficits on exchange rates. Based on US dollar-based real exchange rates in G5 countries and a flexible varying coefficient model, we show that the previously documented weak relationship between fiscal deficits and exchange rates may be the result of additive specifications, and that the relationship is stronger if we allow fiscal deficits to impact real exchange rates non-additively as well as nonlinearly. We find that the speed of exchange rate adjustment toward equilibrium depends on the state of the fiscal deficit; a fiscal contraction in the US can lead to less persistence in the deviation of exchange rates from fundamentals, and faster mean reversion to the equilibrium. Chapter IV proposes a kernel method to deal with the nonparametric regression model with only discrete covariates as regressors. This new approach is based on recently developed least squares cross-validation kernel smoothing method. It can not only automatically smooth the irrelevant variables out of the nonparametric regression model, but also avoid the problem of loss of efficiency related to the traditional nonparametric frequency-based method and the problem of misspecification based on parametric model.

Our ability to understand and predict the fate and transport of contaminants in natural systems is vital if we are to be successful in protecting our water resources. One important aspect of understanding chemical fate and transport in natural systems is identifying key kinetic controls on important redox reactions such as sulfate reduction. Anaerobic microbial activities like sulfate reduction are of particular interest because of the important role they play in the degradation of contaminants in the subsurface. However, current rate estimates for sulfate reduction have a wide range in the literature making it difficult to determine representative rates for a given system. These differences in rate data may be explained by varying kinetic controls on reactions. Push-pull tests were used to evaluate sulfate reduction rates at the wetland-aquifer interface. Anaerobic aquifer water containing abundant sulfate was injected into sulfate-depleted wetland porewater. The injected water was subsequently withdrawn and analyzed for geochemical indicators of sulfate reduction. Complexities in rate data, such as presence of a lag phase, changing rate order and spatial variability, were observed and are hypothesized to be linked to activities of the native microbial population. Subsequent experiments explored the response of native microorganisms to geochemical perturbations using a novel approach to measure directly the effects of a geochemical perturbation on an in situ microbial population and measure rates of resulting reactions. In situ experiments involved colonization of a substrate by microorganisms native to the wetland sediments followed by introductions of native water amended with sulfate and tracer. Experimental results showed that higher sulfate concentrations and warmer seasonal temperatures result in faster sulfate reduction rates and corresponding increases in sulfate reducing bacteria. Findings from this research provide quantitative evidence of how geochemical and microbiological processes are linked in a system not at equilibrium.

Sedimentation rates in sediment cores from Lavaca Bay have been high within the last 1-2 decays within the central portion of the bay, with small fluctuations from river input. Lavaca Bay is a broad, flat, and shallow (<3 m) microtidal estuary within the upper Matagorda Bay system. Marine derived sediment enters the system from Matagorda Bay, while two major rivers (Lavaca & Navidad) supply the majority of terrestrially derived sediment. With continuous sediment supply the bay showed no bathymetric change until the introduction of the shipping channel. Processes that potentially lead to sediment transport and resuspension within the bay include wind driven wave resuspension, storm surges, wind driven blowouts, and river flooding. These processes were assessed using X-radiographs, grain size profiles, and 210Pb and 137Cs geochronology of sediment diver cores. In six cores the upper 10 cm of the seabed has been physically mixed, where as the rest showed a continuous sediment accumulation rate between 0.84-1.22 cm/yr. Sidescan sonar and subbottom chirp sonar data coupled with sedimentological core and grab samples were used to map the location and delineate the sedimentary facies within the estuarine system in depths >1 m. Five sedimentary facies were identified in Lavaca Bay and adjacent bays, they are: 1) estuarine mud; 2) fluvial sand; 3) beach sand; 4) bay mouth sand; and 5) oyster biofacies. Of the five facies, Lavaca Bay consists primarily of estuarine mud (68%). Pre-Hurricane and post-Hurricane Claudette cores were obtained to observe the impact to the sedimentary processes. The north and south Lavaca Bay were eroded by 10 cm and 2-3 cm, respectively. Cox Bay and Keller Bay saw a net deposition of 2-3 cm.

Many construction companies today utilize webcams on their jobsites to monitor and record construction operations. Jobsite monitoring is often limited to outdoor construction operations due to lack of mobility of wired webcams. A wireless webcam may help monitor indoor construction operations with enhanced mobility. The transfer time of sending a photograph from the wireless webcam, however, is slower than that of a wired webcam. It is expected that professionals may have to analyze indoor construction operations with longer interval time-lapse photographs if they want to use a wireless webcam. This research aimed to determine the maximum time interval for time-lapse photos that enables professionals to interpret construction operations and productivity. In order to accomplish the research goal, brickwork of five different construction sites was videotaped. Various interval time-lapse photographs were generated from each video. Worker?s activity in these photographs was examined and graded. The grades in one-second interval photographs were compared with the grades of the same in longer time interval photographs. Error rates in observing longer time-lapse photographs were then obtained and analyzed to find the maximum time interval of time-lapse photography for monitoring construction operations. Research has discovered that the observation error rate increased rapidly until the 60-second interval and its increasing ratio remained constant. This finding can be used to predict a reasonable amount of error rate when observing time-lapse photographs less than 60-second interval. The observation error rate with longer than 60-second interval did not show a constant trend. Thus, the 60-second interval could be considered as the maximum time interval for professionals to interpret construction operations and productivity.

This paper uncovers the relationship between stock markets and exchange rates in seven countries by employing stable aggregate currency (SAC) for the period of 1973- 2004. Ordinary Least Squares (OLS) regression, time series methods, and directed acyclic graphs are applied to the daily data on stock market indices and exchange rates. The findings based on regression analysis show that exchange rate exposure of stock markets is statistically significant when stock indexes in SAC are used. Using an innovation accounting technique, we confirm that stock markets and exchange rates are correlated. Moreover, in most cases stock markets are more exogenous than foreign currency markets, which explains the relatively high percentage of uncertainty in the foreign currency market. Overall, SAC-based models give relatively more accurate and robust results than those which employ stock indices in local currencies, because it is more accurate to convert both variables into the same denominator.

It is widely recognized that livestock industries are vulnerable to intentional or accidental introductions of Foreign Animal Diseases (FADs). Combating disease is difficult because of unknown wildlife-livestock interactions. Feral hogs (Sus scrofa) could harbor and shed disease in areas used by domestic livestock such as cattle (Bos taurus). Extent of risk logically depends on spatio-temporal interactions between species. I used Global Positioning System (GPS) collars on cattle and hogs in combination with a Geographic Information Systems (GIS) for detailed analysis on movement patterns of these 2 species on a ranch in southwestern Texas, USA. Motion-triggered video recorders were also utilized to determine interspecific activity patterns. I tested hypotheses that spatio-temporal distributions of domestic cattle and feral hogs on rangeland overlap and that interspecific contact occurs. If these posits are true, it is possible that introduced pathogens like foot-and-mouth disease (FMD) could be transmitted from feral hogs to cattle. Using a rate of 1 GPS fix/15 min (96 fixes/day), I found that spatial distribution of individual hogs and cattle overlapped on both the 95% and 50% kernel area use among 4 seasons. Both cows and feral hogs used Clay Flat, Clay Loam, and Rolling Hardland more so than other range sites. During Summer 2004, riparian zones were the most used feature, identified at 14% (2,760/19,365) of cattle and 70% (445/632) of hog fixes. Other than brush strips, cattle and feral hogs primarily interacted at riparian zones, fencelines, and roads. There were no direct interspecific contacts evident from GPS data, but 3 cases were recorded from video data. Indirect interspecific contacts that may be sufficient for disease transmission occurred much more frequently (GPS = 3.35 indirect contacts/day, video = cows follow hogs: 0.69 indirect contacts/day and hogs follow cows: 0.54 indirect contacts/day). Research results suggested that both species often travel along the same roads and fencelines to water and food sources, especially during extreme heat and low-precipitation conditions. This research provides basic information needed to improve models for management of FAD outbreaks in the U.S., based on specific knowledge of landscape usage and movement patterns of feral hogs and cattle.

This paper examines how various monetary policy signals such as official discount rate changes¡Bspeeches and monetary aggregate M2 annual growth rate affect the structure of interest rates in Taiwan. The model of the thesis is based on the Svensson model (1994) which is the extension of the parsimonious model defined by Nelson and Siegel (1987). It is being shown, that the term of interest rates, estimated based on Svensson model result in a fault value for Taiwan, due to a unsound bond market especially in the short term and one-year interest rates. There is no proof that unexpected movements in the short end of the yield curve are mainly driven by unexpected changes in the official discount rate. Speeches are found to be a more important determinant for the longer end of the term structure. The conclusion is that central bank communication is an essential part of the conduct of monetary policy.