51 |
The seasonal dynamics of chaetognath assemblages in relation to hydrographic factors in the waters surrounding TaiwanMei, Pu-kai 05 February 2010 (has links)
This study aims to study the species composition and distribution of chaetognaths in the waters surrounding Taiwan January 2005 to July 2006, and to explore the relationship between environmental factors and their dynamic distribution. Waters surrounding Taiwan are affected by monsoons and water masses. In winter, the northwestern Taiwan area is under the impact of low-temperature low-salinity China Coastal Current, but in summer, Taiwan Strait is affected by South China Sea Current going northward with high-temperature and high-salinity. As for eastern waters of Taiwan, Kuroshio current passes throughout the year so it is high-temperature and high-salinity. In July 2006, when three typhoons struck Taiwan, excessive fresh water from land flowed into the ocean and stations along the coast where low in salinity. This study identified a total of 28 species of chaetognath under 14 genera of 4 families, with average abundance at 475 ¡Ó 35 ind./100m3, which shows an obvious change related to seasons, relatively low in winter and spring and high in summer and fall. The seven most dominant species are: Flaccisagitta enflata, Serratosagitta pacifica, Zonosagitta littoralis, Pterosagitta draco, Aidanosagitta regularis, Aidanosagitta bedfordii and Aidanosagitta neglecta, accounting for 85% of the total abundance. The distribution of chaetognath in waters surrounding Taiwan is affected by the different water masses. The northwestern area where China Coastal Current passes through has high abundance but less number and low Shannon diversity index, but the eastern and southern waters dominated by Kuroshio current shows a completely different trend. From the results of multiple regression analysis, it is found that the abundance of chaetognath and F. enflata are in positive correlation with that of the abundance of copepod, indicating that the quantity of food might be a factor affecting the distribution of chaetognath. The second dominant species S. pacifica has no relation with hydrographic or biological factors, and the third dominant species Z. littoralis is in negative correlation with temperature and salinity. Along with the results of indicator species analysis, Z. littoralis can possibly be used as indicators species of China Coastal Current. The three predominant species are dominated by the Stage I and significantly less in other growth stages. The average body lengths (ABL) of F. enflata and S. pacifica are the larger in spring and smaller in fall, with obvious changes with seasons, but that of Z. littoralis is larger in winter and summer and smaller in spring and fall. Different water masses have impacts on distribution of weight mean stage (WMS) and ABL of chaetognath; for example, F. enflata and S. pacifica with the equivalent growth have larger bodies in Kuroshio current than in China Coastal Current, but Z. littoralis which prefers cold water shows an opposite trend. In addition, this study found that abundance, species, Shannon diversity index, WMS and ABL of chaetognath has no differences between day and night, but the succession of water masses in waters surrounding Taiwan may be an important factor affecting the distribution patterns of chaetognaths.
|
52 |
Do Biodiversities of Benthos in Coral Reefs Contributed by Recruitment and Succession?Yang, Shang-lin 06 September 2010 (has links)
Coral reefs have high biodiversity among the many marine ecosystems. Many hypotheses explain marine biodiversity, e.g., the Intermediate Disturbance Hypothesis, the Lottery hypothesis and the Resource Allocation Hypothesis, but there is no mention of the possible role of seasonal effects. Here, we propose the Seasonal Recruitment Hypothesis to explain the possible role of seasonal recruitment and succession in a disturbed ecosystem. In this investigation, we tested several prediction of the hypothesis: a. Does recruitment have seasonal variation? b. Does variable recruiting communities diverge in succession? c. Are high biodiversities of coral reefs contributed by different communities originating from patches created in different seasons?
In this study, we used plastic plates as proxy of empty space generated after disturbance to survey the seasonal patterns of settling benthos. Recruitment plates were placed and retrieved at two-month intervals for two consecutive years. Then, the composition and densities of settled taxa were estimated. The PRIMER software was used to compare the community similarities. We looked for possible seasonal patterns in each benthic populations but found few not real examples of such. Although there is difference between communities started in different seasons, no cyclic pattern in similarity was found by MDS plots in two years of recruitment communities. There are variations of recruitment community between different year and month, and the community structures converged after succession. These results do not support the prediction of the Seasoanl Recruitment Hypothesis.
|
53 |
Spatiotemporal distribution of larval fish assemblage in the coastal waters off Kaohsiung and Pingtung, TaiwanWu, Chia-Ching 12 September 2012 (has links)
To clarify the spatiotemporal distribution of the winter and spring larval fish assemblage in the coastal waters off Kaohsiung and Pingtung, Taiwan, larval fishes were collected during four research cruises by conducting 35 tows of the larval net in coastal waters off Zuoying, Linyuan, Linban and Fangliao in January and March 2009 and in coastal waters off Linyuan adjacent to the Kaoping River estuary in January and March 2010. Water temperature, salinity and dissolved oxygen were measured during the sampling of the fish larvae. Seawater samples were also collected for analyzing concentrations of nutrient salts.
In 2009, a total of 2,023 fish larvae, representing 38 families and 74 species, were collected. The fish larvae assemblage exhibited seasonal variation in both abundance and species composition. The abundance (460 ind./1000m3) and the number of species (34 families and 66 species) of the fish larvae collected in March were higher than those (28 ind./1000m3, 14 families and 27 species) collected in January. Fish larvae also exhibited spatial variation in species composition. In January, the most dominant families of fish larvae were: Myctophidae off Linyuan, Sparidae off Linban and Nomeidae off Fangliao. In March, in the northward coastal waters off Linyuan Scombridae was the most dominant family, and in the southward coastal waters off Linyuan, Clupeidae and Sillaginidae were the dominant families. No significant differences existed in the abundance of fish larvae among the sampling areas, but the abundance of fish larvae in the sampling sites off Linyuan and Linban tended to be strongly influenced by tide.
In 2010, a total of 1,959 fish larvae, representing 39 families and 59 species, were collected. These fish larvae showed diurnal and seasonal variations in abundance and in species composition. The abundance (767 ind./1000m3) and the number of species (39 families and 55 species) of the fish larvae in March were higher compared with those (26 ind./1000m3, 16 families and 25 species) in January. Moreover, the abundance of fish larvae in the nighttime was higher than that in the daytime. In March, the most dominant family in the daytime was Serranidae, whereas the most dominant family in the nighttime was Myctophidae, indicating the diurnal migration of Myctophidae these larvae.
Cluster analysis indicated that the abundance and species composition of the fish larvae differed between January and March in 2009. The difference in species composition among the four sampling areas was only found significant for the fish larvae collected in the coastal waters off Fangliao in winter, and the most influenced families were Nomeidae and Myctophidae. In 2010, seasonal variations were found in the abundance and species composition of the fish larvae, and the abundance of the fish larvae showed the difference between nearshore and inshore sampling sites in the nighttime in winter. In spring, the fish larvae were all inshore fishes, but the species composition had annual variation. The temperature and salinity data obtained in the sampling sites conformed to the surface seawater of South China Sea, indicating that the occurrence of the dominant family Scombridae may be related to the seawater of South China Sea.
|
54 |
Seasonal and diel vertical distributions of copepod assemblages in relation to environmental factors in Tapong Bay, southwestern TaiwanHsu, Pei-Kai 28 January 2008 (has links)
The small-scale vertical migration patterns and spatiotemporal variations of copepods in the Tapong Bay, southwestern Taiwan, from 2003 to 2005 were studied. The differences in species composition and abundance of copepods before and after the removal of oyster culture racks in relation to tides, hydrography and other environmental factors were also compared and herein discussed. Tapong Bay has distinct dry (October to April) and wet (June to August) seasons and exhibits apparent inter-annual variation, cold, saline and low Chl a concentration in dry season, and vice versa in wet season. Most copepod species displayed normal diel vertical migration, descending to the deeper water during daytime and ascending to near surface water at night. Copepods were always more abundant at night than during daytime. Higher abundance but smaller species number of copepods were found during ebb than flood tides. In all, 123 copepod species belonging to 18 families and 31 genera were identified. Oithona oculata, Parvocalanus crassirostris, Acartia sinjiensis, Acartia sp., Bestiolina amoyensis and copepod nauplius were predominant and together they composed 74% of the total number of copepods. These dominant species showed apparent seasonal changes, with higher abundance in autumn and winter. Copepod assemblage also showed apparent difference between stations. Warm-saline-coastal species dominated in the outer region, while small-size taxa and common species of estuaries and aquaculture ponds dominated in the inner bay. Results of indicator species analysis could possibly recognize the area affected by tides and water masses, and identified Acrocalanus gracilis to be the indicator species of flood tide and outer region of the bay, and Acartia sinjiensis the indicator species of ebb tide and inner bay. Our results showed that after the removal of oyster culture racks the species number and abundance of copepods were higher but the seasonal and spatial differences in abundance became smaller. Furthermore, the increase in abundance of zooplankton and copepods in the Bay after the removal of oyster culture racks might be due to the absence of oyster population which exerts great filter¡Vfeeding impact on phytoplankton, and decrease of predation pressure from moon-jelly that usually aggregated in the inner Bay and settled down their polyps on the oyster racks but disappeared after the removal.
|
55 |
Seasonal variation in cause-specific sexually transmitted disease morbidity in Hong Kong (1998-2001): are thereany long holiday effects on the morbidity due to Neisseriagonorrhoeae?方月平, Fong, Yuet-ping. January 2002 (has links)
published_or_final_version / Medical Sciences / Master / Master of Medical Sciences
|
56 |
Tests for seasonal differencing with a break-point伍子文, Ng, Tze-man. January 1993 (has links)
published_or_final_version / Statistics / Master / Master of Philosophy
|
57 |
Buying Locally Grown and Eating Seasonally in ArizonaHongu, Nobuko, Turner, Rachel J., Martinez, Cathy L., Suzuki, Asuka, Gonsalves, Kimberly A. 10 1900 (has links)
6 pp. / More and more consumers are choosing to buy locally produced foods. Health and environment conscious consumers believe locally grown foods are healthier, fresher, and are better tasting than foods that have endured many miles of transport. Buying locally also helps communities by stimulating local economies and protecting the environment. This article outlines the benefits of buying locally grown food and eating seasonally in Arizona. A recipe that is easy and affordable using local produce is included. An Arizona seasonal produce availability calendar is included in the Appendix.
|
58 |
A seasonal goods inventory model with price-cuttingPalmer, Allyn Jon 12 1900 (has links)
No description available.
|
59 |
Vitamin D status in winter and summer among nurses and implications for cancer etiologyWALLINGFORD, SARAH 23 September 2009 (has links)
Background: Recent research indicates that inadequate vitamin D status may incur increased cancer risk, particularly for breast and colon cancer. Cutaneous generation of vitamin D through direct absorption of summer sunlight is considered the principal source of vitamin D; however, at latitudes above 40ºN, UVB rays are insufficient to permit cutaneous synthesis during winter. Vitamin D can also be obtained from natural and fortified dietary sources and through supplement use, although dietary reference intake values do not seem to compensate for restricted cutaneous synthesis in winter.
Objectives: To determine the prevalence of vitamin D insufficiency post-winter and post-summer, to determine the seasonal variation in 25-hydroxyvitamin D (25(OH)D) levels, and to investigate determinants of 25(OH)D concentrations.
Methods: A cross-sectional study of vitamin D status post-winter and post-summer was conducted among 49 premenopausal rotating shift nurses at Kingston General Hospital. In each season, vitamin D levels were measured using a radioimmunoassay to quantify serum 25(OH)D from fasting blood samples, and personal, lifestyle, and dietary factors potentially influencing vitamin D levels were assessed from a self-report questionnaire. Nurses were classified as vitamin D sufficient (>30ng/mL) or insufficient (≤30ng/mL).
Results: A statistically significant difference was found between mean serum 25(OH)D concentrations post-winter (32.6ng/mL) and post-summer (42.5ng/mL) (p=0.0003). The prevalence of vitamin D insufficiency post-winter was 49% compared to 24% post-summer p=0.02). Tanning bed use was associated with significantly higher winter serum 25(OH)D levels was tanning bed, while controlling for age, BMI, and vitamin D-fortified yogurt consumption (R2=0.41, p=0.007). For summer, predictors of higher serum 25(OH)D levels were supplement use and tanning bed use in the past six months, while controlling for age, BMI, and beef/veal consumption (R2=0.53, p=0.001).
Conclusions: Vitamin D insufficiency was prevalent both post-winter and post-summer, but with much higher prevalence post-winter. Controlling for age and BMI, tanning bed use was a determinant of serum 25(OH)D concentrations in both seasons, while fortified yogurt consumption also contributed in winter, and beef/veal consumption and supplement use contributed in summer. These findings support the need to improve vitamin D status among this population, and to increase the dietary reference intake values and supplement recommendations. / Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2009-09-22 15:35:27.652
|
60 |
Characteristic behaviour of slow moving slidesMansour, Mohamed Unknown Date
No description available.
|
Page generated in 0.0548 seconds