The concentrations of atmospheric carbonyls were studied by the LpDNPH-Cartridge and the microcomputer air sampling device at Nan-Chie ¡BHsiung-Kong¡BRen-Wu and Lin-Yuan sites. Factor analysis was also used to determine the source apportionment in the Kaoshiung area. The results showed that the highest concentrations of carbonyls was acetaldehyde (27.83, 28.91, 11.46 and 10.06 £gg/m3) at four sites, followed by formaldehyde (5.03, 6.92, 7.88 and 6.59 £gg/m3), respectively. The highest concentration of total carbonyls at Nan-Chie and Hsiung-Kong was 65.42 £gg/m3 and 85.09 £gg/m3 in summer, the lowest concentration was 25.06 £gg/m3 and 37.12 £gg/m3 in winter, relatively, the highest concentration of total carbonyls at Ren-Wu and Lin-Yuan was 49.94 £gg/m3 and 55.24 £gg/m3 in winter, the lowest concentration was 24.48 £gg/m3 and 11.78 £gg/m3 in autumn. Additionally, peak rush hours of the traffics, either in the morning or at night, would result in increased concentration of Carbonyls. The results of factor analysis showed that the principle sources at Nan-Chie were traffic exhausts (diesel and gasoline vehicle) and stationary sources (metal assembly, waste treatment, pulp and restaurant). The principle sources at Hsiung-Kong were traffic exhausts (diesel, and gasoline vehicle), stationary sources (leather, chemical process and restaurant). The main sources at Ren-Wu were traffic exhausts (gasoline vehicle) and stationary sources (metal assembly, chemical process and restaurant). The main sources at Lin-Yuan were traffic exhausts (diesel vehicle) and stationary sources (metal assembly, leather, steel production and restaurant).

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Recent years have seen considerable advances in the study of biological rhythms and the underlying molecular mechanisms that drive the daily and seasonal physiology of vertebrates. Amongst teleosts the majority of work in this field has focused on the model species the zebrafish to characterise clock genes and the molecular feedback loop that underpins circadian rhythms and physiology. Daily profiles of clock gene expression in a wide variety of tissues and cell types are now relatively well described. However the zebrafish is a tropical species that does not display distinct seasonality and therefore may not be the species of choice to investigate the entrainment of circannual physiology. In contrast, Atlantic salmon is a highly seasonal teleost that displays considerable temporal organisation of most physiological processes. In salmonids photoperiod is widely known to synchronise physiology to the environmental conditions and as such photoperiod manipulation is routinely used by the salmon industry throughout the production cycle to control and manipulate spawning, smoltification and puberty. Previous studies in salmonid species have already identified a set of clock genes that are linked to these seasonal physiological processes. However, to date, the molecular mechanisms regulating daily and seasonal physiology are largely unknown despite the strong commercial relevance in the Atlantic salmon. In the Atlantic salmon, Davie et al (2009) was the first to report the photoperiod dependent circadian expression of clock genes (Clock, Bmal and Per2 and Cry2) in the brain of the Atlantic salmon. In the same investigation the expression of clock genes was reported in a wide variety of peripheral tissues, however 24h profiles of expression in peripheral tissues were not characterised. In order to examine further the role of seasonal photoperiod on the circadian expression of clock genes, the present work first aimed to characterise diel profiles of Clock, Per1 and Per 2 expression in the brain together with plasma melatonin levels in II Atlantic salmon acclimated to either long day (LD), short day (SD), 12L:12D (referred to as experiment 1 throughout) and SNP (referred to as experiment 2 throughout). Photoperiod dependent clocks were also investigated in peripheral tissues, namely in the fin and liver. Results showed circadian profiles of melatonin under all photoperiods. In experiment 1 both Clock and Per2 displayed significant circadian expression in fish exposed to LD. This is in contrast to previous results where rhythmic clock gene expression was observed under SD. In addition, clock gene expression differed in response to experimental photoperiod in the liver, and diel rhythm differed to that of the brain. No rhythmic expression was observed in the fin. Levels of plasma melatonin exhibited a circadian rhythm peaking during the nocturnal phase as expected. However the amplitude of nocturnal melatonin was significantly elevated under LD (experiment 1) and the SNP long day photoperiod and 2010 autumnal equinox samples (experiment 2). Overall results from these experiments suggested that the control of clock gene expression would be photoperiod dependent in the brain and the liver however photoperiod history is also likely to influence clock gene expression. Interestingly, the gradual seasonal changes in photoperiod under SNP did not elicit similar profiles of clock gene expression as compared to experimental seasonal photoperiods and clock gene expression differed between experimental photoperiod and SNP treatments. In experiment 2 significant seasonal differences were also observed in the amplitude of individual clock gene expression. The mechanisms underlying this and potential impact on seasonal physiology are unknown. Developmental changes such as the smoltification process or abiotic factors such as temperature or salinity should be further investigated. In mammals previous work has focused on the molecular switch for photoperiod response and regulation of thyroid hormone bioactivity via deiodinase mediated conversion of T4 to the biologically active form T3. In mammals and birds expression of key seasonal molecular markers i.e. Tsh, Eya3 and Dio2, are up-regulated hours after exposure to the first LD and III persist under chronic LD conditions. In order to confirm the involvement of these genes in the seasonal photoperiodic response in salmon, a microarray study was first carried out. Results displayed transcriptome level differences in the seasonal expression of a wide variety of target genes including Eya3 and Dio1-3 in relation to LD and SD photoperiod suggesting that these genes may have a conserved role in salmon. qPCR validations of selected genes of interest were then performed (Dio1, Dio2 and Dio3, Eya3 and Tshover diel cycles in fish exposed to LD and SD photoperiod (autumn acclimated fish). In addition an unrelated qPCR study was undertaken in salmon parr acclimated to LD, 12L12D and SD photoperiod (spring acclimated fish)(Dio2, Eya3 and Tsh. Consistent with findings obtained in other vertebrate species, circadian expression of Dio2 was observed under LD. However expression of Eya3 and Tsh appeared to be dependent on photoperiod history prior to acclimation to the experimental photoperiods as already suggested for clock gene expression in this thesis. This is potentially a consequence of direct regulation by clock genes. To our knowledge, this is the first report on the expression of key molecular components that drive vertebrate seasonal rhythms in a salmonid species. The thesis then focused on another key component of the photoneuroendocrine axis in fish, the pineal organ. In the Atlantic salmon, as in other teleosts the photoreceptive pineal organ is considered by many to be essential to the generation, synchronisation and maintenance of circadian and seasonal rhythms. This would be primarily achieved via the action of melatonin although direct evidence is still lacking in fish. In salmonids the production of pineal melatonin is regulated directly by light and levels are continually elevated under constant darkness. In non salmonid teleosts the rhythmic high at night/ low during day melatonin levels persists endogenously under constant conditions and is hypothesised to be governed by light and intra- pineal clocks. The aims of the present in vitro and in vivo trials were to determine if circadian clocks and Aanat2 expression, the rate limiting enzyme for melatonin IV production, are present in salmon, test the ability of the pineal to independently re-entrain itself to a different photoperiod and establish whether the candidate clock genes and Aanat2 expression can be sustained under un-entrained conditions. Expression of clock genes was first studied in vitro with pineal organs exposed to either 12L:12D photoperiod, reversed 12D:12L photoperiod and 24D. Clock gene expression was also determined in vivo, in fish exposed to 12L:12D. Results were then contrasted with an in vitro (12L:12D) investigation in the European seabass, a species displaying endogenous melatonin synthesis. Results revealed no rhythmic clock gene (Clock, per1 and per2) expression in isolated salmon pineals in culture under any of the culture conditions. In the seabass, Clock and Per1 did not also display circadian expression in vitro. However rhythmic expression of Cry2 and Per1 was observed in vivo in the salmon pineal. This suggested some degree of extra-pineal regulation of clocks in the Atlantic salmon. In terms of Aanat2 no rhythmic expression was observed in the Atlantic salmon under any experimental conditions while rhythmic expression of Aanat2 mRNA was observed in seabass pineals. This is consistent with the hypothesis that in salmonids AANAT2 is regulated directly at the protein level by light while in other teleosts, such as seabass, AANAT2 is also regulated by clocks at a transcriptional level.

Firms that face seasonal demand account for an important fraction of the U.S. economy. However, there is surprisingly little evidence on these firms' financing decisions. Yet, studying these decisions provides a natural setting to shed light on the types of capital (i.e. cash or debt) that firms use to manage short-term financing needs. Using seasonal firms as a setting to examine this issue, I show that seasonal financing needs are met with debt with low exposure to information asymmetry, such as short-term debt and trade credit. I further show that cash reserves, which have high carrying costs and can at time lead to agency problems, are not used for seasonal financing needs. Further, as financial flexibility theory would predict, I document that seasonal firms maintain more conservative financial policies to increase the ability to use debt for short-term financing needs. Specifically, seasonal firms are less levered and have long-term debt with a longer average maturity. Further, seasonal firms adjust toward leverage targets slower during fiscal quarters when debt is used for short-term financing. Overall, my findings indicate that firms minimize costs associated with short-term financing needs by using debt with low issuance costs and the use of this debt impacts the overall capital structure of the firm.

In developing a water quality monitoring program, the sampling frequency chosen should be able to reliably detect changes in water quality trends. Three datasets are evaluated for Minimal Detectable Change in surface water quality to examine the loss of trend detectability as sampling frequency decreases for sites within the National Park Service's Sonoran Desert Network by re-sampling the records as quarterly and annual datasets and by superimposing step and linear trends over the natural data to estimate the time it takes the Seasonal Kendall Test to detect trends of a specific threshold. Wilcoxon Rank Sum analyses found that monthly and quarterly sampling consistently draw from the same distribution of trend detection times; however, annual sampling can take significantly longer. Therefore, even with a loss in power from reduced sampling, quarterly sampling of Park waters adequately detects trends (70%) compared to monthly whereas annual sampling is insufficient in trend detection (30%).

Precipitation (P) and precipitable water (W) are important components of the hydrological cycles in the earth system, and their seasonal cycles are closely related to monsoon circulations over monsoon regions. Through theoretical analyses and extensive analysis of data from in-situ measurements, satellite remote sensing, and regional reanalysis, significant progress has been made (via four peer-reviewed publications) in four areas related to P, W, and monsoon onset and retreat. First, based on the normalized W index, a novel unified method is proposed to determine global monsoon onset and retreat dates. The results are consistent with those obtained from different local criteria. Second, theoretical and data analyses demonstrate that, because of the large annual range of temperature, W can increase from winter to summer anywhere except in the tropics, including both monsoon and nonmonsoon regions. Third, while the seasonal variation of P is, in general, caused by complex processes (e.g., atmospheric circulations), thermodynamic derivations and data analysis demonstrate that the variation of P from winter to summer can be easily understood from the comparative strength between the change of water vapor and the change of temperature. In monsoon regions, the change of water vapor from winter to summer is much greater than the change of temperature, so P has an in-phase relation with W. While in some of the nonmonsoon regions, where winter is the rainy season, the change of temperature is much greater than the change of water vapor, leading to an out-of-phase relation between P and W, and, relative to summer, the coldness of the winter air is much more significant than its dryness. Finally, the satisfactory performance of the globally unified monsoon index can be understood by comparing the seasonal cycles of P and W. The significant positive correlations between P and W at seasonal and synoptic scales imply that W has the ability to indicate both the means and the interannual variations of the monsoon onset and retreat. Since large increase of W from winter to summer can occur in both monsoon and nonmonsoon regions, the global monsoon regions cannot be obtained from the seasonal change of W.

The ability of animals to contend with unpredictable seasonal shifts in quality and quantity of prey has implications for the conservation of wildlife. Steller sea lions(Eumetopias jubatus) were subjected to different quantities and qualities of food to determine what physiological and endocrine responses would occur and whether they differed between season (summer and winter) or diet (high-lipid Pacific herring Clupeapallasi vs. low-lipid Walleye Pollock Theragra chalcogramma). Eight females were divided among two groups. One (Group H) were fed herring for 28 days (baseline), then received a reduced caloric intake for a subsequent 28 days (restriction) to induce a 15%loss of body mass. The second (Group P) were also fed herring during the baseline followed by a reduced isocaloric diet of pollock during the restriction. Both groups subsequently returned to their baseline intake of herring for a 28-day controlled re-feeding. The two groups of sea lions lost identical mass during restrictions independent of species eaten, but did differ in the type of internal energy reserve (protein vs. lipids) they predominantly used. Group H lost significantly more lipids and less lean mass than Group P in both seasons. In summer, Group H also increased activity levels and decreased thermoregulation capacity to optimize energy allocation. No such changes were observed for Group P whose capacity to adjust to the reduced caloric intake seemed to have been blocked by the pollock diet. During winter, the sea lions spared energy allocated to activity (especially Group H) and preserved thermoregulation capacity. Changes in body mass was negatively related to free cortisol and positively related to IGF-1 in winter, but only IGF-1 was related to changes in mass in summer when lean mass regulation seemed more important. Levels of IGF-1 were associated with changes in protein metabolism in both seasons for both groups, but changes in body condition were never explained by the measured metabolites or hormones. The capacity to compensate for mass loss was seasonally dependent with sea lions displaying compensatory growth (by restoring lipid stores) in winter but not in summer. Summer appears to be a more difficult season for sea lions to recover from mild nutritional stress. These physiological findings can be used to refine bioenergetic models needed for the conservation of Steller sea lion populations.

Three key questions are identified and answered in this paper. Firstly, have the average annual temperatures in the Prince George Region changed in recent years? Secondly, have the seasonal flow rates changed for local waterways? Lastly, have the timing of the annual flood cycles in the Prince George, British Columbia changed? By reviewing data from local weather and hydrological monitoring stations, this paper identifies that the average annual temperature in Prince George, British Columbia has not only increased but also shifted to a pattern of warmer winters and cooler summers. The flow rates for the region were seen to have been altered as well, indicating increased flow rates in the winter and early spring and decreased flow rates in the summer and early fall. The magnitude of flood frequency events such as the 10, 25 and 100 year flood occurrence does not seem to have the increased in recent years.

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