Use of state‐space modelling to identify ecological covariates associated with trends in pinniped demography     

Marjolaine Caillat  Line Cordes  Paul Thompson  Jason Matthiopoulos  Sophie Smout 《水产资源保护:海洋与淡水生态系统》2019,29(Z1):101-118

Intake and discharge nutrient loads at three intensive shrimp farms     

Christopher Jackson  Nigel Preston  & Peter J Thompson 《Aquaculture Research》2004,35(11):1053-1061

This study was conducted to help provide a framework for Australian regulation of shrimp farm siting and discharges. Monitoring of farm water usage, and intake and discharge water quality was conducted at three commercial intensive shrimp farms, chosen to represent different operating environments, latitudes, cultured species and management styles. Weekly samples were taken over 3 years, for 3–12 months at each farm, to investigate intake and discharge concentrations and loads of total suspended solids (TSS), total nitrogen (TN) and total phosphorus (TP). Mean water exchange was 1.4 ML ha^?1 day^?1 (about 10% day^?1) at the first farm studied and 0.5 ML ha^?1 day^?1 (about 3.6% day^?1) at the others. Farm mean discharge concentration varied as follows: TSS, from 36.9 to 119 mg L^?1; TN, from 2.1 to 3.1 mg L^?1 and TP, from 0.22 to 0.28 mg L^?1. Farm mean intake concentrations were from 11% to 91% of equivalent mean discharge concentration (for TN at Farm B and TSS at Farm C respectively). Mean net discharge loads, related to area of production ponds at each farm, varied as follows: TSS, from 4.8 to 85.7 kg ha^?1 day^?1; TN, from 1 to 1.8 kg ha^?1 day^?1 and TP, from 0.11 to 0.22 kg ha^?1 day^?1. The highest net loads of TSS, TN and TP were all from the farm with the highest water exchange rate, located on a coastal river, and studied during a year of high rainfall with associated poor water quality. These results can be used to help predict likely discharge characteristics for new shrimp farms, and provide a benchmark against which to evaluate future improvements in shrimp farm environmental management.  相似文献   

Ultrastructural morphogenesis of salmonid alphavirus 1     

T K Herath  H W Ferguson  K D Thompson  A Adams  R H Richards 《Journal of fish diseases》2012,35(11):799-808

Studies on the ultrastructural morphogenesis of viruses give an insight into how the host cell mechanisms are utilized for new virion synthesis. A time course examining salmonid alphavirus 1 (SAV 1) assembly was performed by culturing the virus on Chinook salmon embryo cells (CHSE‐214). Different stages of viral replication were observed under electron microscopy. Virus‐like particles were observed inside membrane‐bound vesicles as early as 1 h following contact of the virus with the cells. Membrane‐dependent replication complexes were observed in the cytoplasm of the cells, with spherules found at the periphery of late endosome‐like vacuoles. The use of intracellular membranes for RNA replication is similar to other positive‐sense single‐stranded RNA (+ssRNA) viruses. The number of Golgi apparatus and associated vacuoles characterized by ‘fuzzy’‐coated membranes was greater in virus‐infected cells. The mature enveloped virions started to bud out from the cells at approximately 24 h post‐infection. These observations suggest that the pathway used by SAV 1 for the generation of new virus particles in vitro is comparable to viral replication observed with mammalian alphaviruses but with some interesting differences.  相似文献   

Analysis of landscape pattern change trajectories within areas of intensive agricultural use: case study in a watershed of southern Québec, Canada   总被引：1，自引：0，他引：1  

Julie Ruiz  Gérald Domon 《Landscape Ecology》2009,24(3):419-432

This study aimed at capturing the spatial variability of landscape patterns and their trajectories of change from 1950 to 2000 within a watershed, which is representative of areas of intensive agricultural use. After an analysis of landscape features changes for the entire watershed based on aerial photographs, hierarchical clustering analysis provided a typology of landscape patterns for the cadastral lots. Following that, the trajectory of change of each lot was characterized (nature, importance, direction, rate of change). Seven types of landscape patterns are distinguished by the relative importance of different classes of landscape features and 51 trajectories of change were identified for the lots. The analysis shows that although the majority of lots were subjected to a homogenization of their landscape patterns since 1950, this trend is not entirely uniform and that since 2000 it occurs alongside trends towards diversification of certain landscape features on some lots. Furthermore, nearly a third of the lots are not following the main trajectories of change detected. Thus, the results suggest that extrinsic forces (policies, technologies) that are directing main changes in areas of intensive agricultural use toward uniformity could be modulated by internal forces (uses and values of the population). A better understanding of theses internal forces seems crucial to manage landscapes. From a methodology standpoint, although the hierarchical clustering analyses appear useful for understanding the spatial and temporal variability of landscape patterns, particular attention must be given to validating the typology chosen to characterize them.  相似文献   

Comparative forcing of Hydrangea macrophylla ‘Bailer’ as a florist's hydrangea     

Neil Anderson  Julie Weiland  Jill Pharis  Wendy Gagné  Elisabeth Janiga  Mary Jo Rosenow 《Scientia Horticulturae》2009

‘Bailer’ (Endless Summer™) is a new, pink- or blue-flowered hydrangea that flowers on new wood continuously throughout the growing season. It is also winter-hardy in northern, temperate climates (USDA Z4). Use of Endless Summer as a florist's potted hydrangea would provide consumers with a dual-use product (flowering potted plant, landscape shrub). The objectives were to determine if Endless Summer could be forced as a florist's hydrangea using two forcing regimes (immediate, standard), two soil pH regimes, and two pinching treatments. ‘Merritt Supreme Pink’ (pink), ‘Blue Danube’ (blue), and Endless Summer (blue, pink) were forced under immediate (no cold treatment, short- and long-day photoperiods) and standard (6 weeks cold, 4 °C to overcome dormancy) conditions. Since commercial liners were not yet available, cuttings of Endless Summer were used in the immediate forcing experiment. Days to visible flower bud, first color, full flower were recorded, as well as height, no. of branches, no. of flowers, and flower size. In the immediate forcing experiment, only Endless Summer produced flowers. Cultivars differed significantly (P < 0.001) for days to visible flower bud, days to first color, days to full flower, and height. The number of flowers and flower size were not significantly different among pink cultivars. In the standard forcing experiment, Endless Summer reached days to visible flower bud, days to first color, and days to full flower significantly earlier than either comparison, although it exhibited weaker stems and less intense flower pigmentation. Pinching (blue pH) had a significant effect on all traits except the days to full flower and flower size, although no pinching treatment was significant for pink pH. Photoperiod was significant only for the days to visible flower bud (pink pH), days to full flower (blue pH), and final height (blue pH). Further research is needed before Endless Summer can be grown as a dual-use florist's potted hydrangea with acceptable quality.  相似文献   

Towards an integrated understanding of green space in the European built environment     

P. James  K. Tzoulas  M.D. Adams  A. Barber  J. Box  J. Breuste  T. Elmqvist  M. Frith  C. Gordon  K.L. Greening  J. Handley  S. Haworth  A.E. Kazmierczak  M. Johnston  K. Korpela  M. Moretti  J. Niemelä  S. Pauleit  M.H. Roe  J.P. Sadler  C. Ward Thompson 《Urban Forestry & Urban Greening》2009,8(2):65-75

In recent years social, economic and environmental considerations have led to a reevaluation of the factors that contribute to sustainable urban environments. Increasingly, urban green space is seen as an integral part of cities providing a range of services to both the people and the wildlife living in urban areas. With this recognition and resulting from the simultaneous provision of different services, there is a real need to identify a research framework in which to develop multidisciplinary and interdisciplinary research on urban green space. In order to address these needs, an iterative process based on the delphi technique was developed, which comprised email-mediated discussions and a two-day symposium involving experts from various disciplines. The two outputs of this iterative process were (i) an integrated framework for multidisciplinary and interdisciplinary research and (ii) a catalogue of key research questions in urban green space research. The integrated framework presented here includes relevant research areas (i.e. ecosystem services, drivers of change, pressures on urban green space, human processes and goals of provision of urban green space) and emergent research themes in urban green space studies (i.e. physicality, experience, valuation, management and governance). Collectively these two outputs have the potential to establish an international research agenda for urban green space, which can contribute to the better understanding of people's relationship with cities.  相似文献   

Bibliometric Profile of an Agbioscience Research Enhancement Grant Program     

Julie L. Aldridge 《Journal Of Agricultural & Food Information》2019,20(2):98-128

This study is a bibliometric analysis of journal articles generated from an intramural grant program in the agbiosciences. Using citation analysis and bibliometric mapping, the study analyzes 515 journal articles published from 1999 to 2017. Results show the growth of journal article output, identify the major research fields and topics, describe national and international authorial and institutional collaborations, and quantify the performance and impact of the article output. The grant program’s journal article output presents a multi-disciplinary range of scholarly publications that reflect the disciplines of The Ohio State University’s College of Food, Agricultural, and Environmental Sciences, which houses the grant program.  相似文献   

Carotenoid changes of intact watermelons after storage     

Perkins-Veazie P  Collins JK 《Journal of agricultural and food chemistry》2006,54(16):5868-5874

Watermelon contains lycopene, a red carotenoid pigment that has strong antioxidant properties. The lycopene content of watermelon is substantial, contributing 8-20 mg per 180 g serving. There are no reports on carotenoid changes in whole watermelon during storage. Three types of watermelon, open-pollinated seeded, hybrid seeded, and seedless types, were stored at 5, 13, and 21 degrees C for 14 days and flesh color, composition, and carotenoid content were compared to those of fruit not stored. Watermelons stored at 21 degrees C had increased pH, chroma, and carotenoid content compared to fresh fruit. Compared to fresh fruit, watermelons stored at 21 degrees C gained 11-40% in lycopene and 50-139% in beta-carotene, whereas fruit held at 13 degrees C changed little in carotenoid content. These results indicate that carotenoid biosynthesis in watermelons can be affected by temperature and storage.  相似文献   

Use of stem diameter variations to detect plant water stress in tomato   总被引：3，自引：0，他引：3  

M. Gallardo  R. B. Thompson  L. C. Valdez  M. D. Fernández 《Irrigation Science》2006,24(4):241-255

The sensitivity of stem diameter variations (SDV) measured with linear variable transducer (LVDT) sensors as indicators of plant water status in tomato was evaluated. Two tomato crops were grown sequentially in a sandy loam soil in an unheated plastic greenhouse. These were an autumn–winter tomato crop (autumn crop) and a spring–summer tomato crop (spring crop). One drying cycle of 61 days was imposed to the autumn crop in winter at 92 days after transplanting (DAT). Two drying cycles, each of 29 days, were applied to the spring crop, to young (58 DAT) and mature plants (121 DAT). For each drying cycle, four replicate plots did not receive irrigation, and four were well watered. During each drying cycle, LVDT sensors continuously measured SDV, and daily measurements were made of leaf (Ψ _leaf) and stem water potential (Ψ _stem). SDV data was interpreted using the SDV-derived indices, maximum daily shrinkage (MDS) and stem growth rate (SGR). The response of SDV-derived indices to water deficit differed with (1) climatic conditions during stress imposition and (2) crop age. In the winter drying cycle of the autumn crop, the responses of the SDV-derived indices to soil drying were relatively small and slower than Ψ _leaf and Ψ _stem. Under warmer conditions, the SDV-derived indices were much more responsive to soil drying. In rapidly growing young plants, where SDV was characterized by high SGR and small MDS, SGR was the most sensitive SDV-derived index. In more mature plants with little stem growth, MDS was the most sensitive SDV-derived index. In mature plants grown in warm to hot conditions, MDS (1) responded at a similar time or earlier than Ψ _leaf and Ψ _stem and (2) had larger “signal” values (ratio of values from unwatered to control plants) than Ψ _leaf and Ψ _stem. However, there was appreciably more “noise” (coefficient of variation, CV) associated with the SDV-derived indices, giving lower “sensitivity” values, determined from “signal” to “noise” ratios, than for Ψ _leaf and Ψ _stem. Regression analysis between MDS of well-watered plants and climatic variables gave best results for a linear relationship between MDS and daily maximum vapor pressure deficit. There were strong linear relationships between MDS and Ψ _leaf for each drying cycle. The slopes of these relationships differed with crop age indicating that there was no constant relationship between MDS and Ψ _leaf for a whole season. Overall these results demonstrated that MDS and SGR can be sensitive indicators of the water status of tomato crops under conditions of moderate to high evaporative demand. However, the variability associated with the SDV-derived indices and the changing MDS–Ψ _leaf relationship with crop age represent major issues regarding the development of irrigation scheduling protocols for tomato.  相似文献   

The economic impacts of blackbird (Icteridae) damage to sunflower in the USA     

Karina Ernst  Julie Elser  George Linz  Hans Kandel  Jason Holderieath  Samantha DeGroot  Steven Shwiff  Stephanie Shwiff 《Pest management science》2019,75(11):2910-2915

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