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William D. Boelter MD Beth Ann Burt Elaine B. Spector David R. Hinton Zdena Pavlova Atsuko Fujimoto 《黑龙江环境通报》1990,10(11):703-715
A pregnant woman with indeterminate Duchenne muscular dystrophy (DMD) carrier status, but with DMD diagnosed in her deceased brother (unavailable for study), presented for prenatal diagnosis, intending to continue the pregnancy only if proven unaffected with DMD with near absolute certainty. Creatine kinase (CK) assays to clarify carrier status were inconclusive. Male sex in the fetus was identified, but DNA restriction fragment length polymorphism (RFLP) analysis was not yet available to this centre to investigate the possible transmission of the DMD gene, and the pregnancy was terminated. Tissue histology and dystrophin protein analysis demonstrated the absence of DMD. In a situation with proven maternal carrier status, future fetal inheritance of the opposite maternal X chromosome would indicate the presence of DMD. However, maternal carrier status remained in doubt through a second pregnancy, even with RFLP studies, and was finally established when dystrophin analysis confirmed the presence of DMD in the second fetus. Histologic findings are presented, contrasting features in the two fetuses. The value of dystrophin analysis for establishing the diagnosis of fetal DMD, in this case proving maternal carrier status in a difficult situation, and for demonstrating DMD gene:RFLP haplotype relationships is illustrated. 相似文献
5.
Spatial and temporal patterns of predation on seeds of the seagrass Phyllospadix torreyi S. Watson were quantified at four sites near Santa Barbara, California, USA. Over a period of four flowering seasons during
1995 to 1998, monthly patterns of seed fall and intensity of seed predation were similar among sites, but were temporally
quite variable. Abundance of dispersed seeds varied greatly both among seasons and years. Within any one year, seeds were
present in the environment every month, but they peaked in abundance during the fall months following the annual flowering
period. Seeds were more abundant during the earlier years of the study. The intensity of predation steadily increased throughout
the study period, from a low of ≤10% seeds consumed during 1995 to ∼50% consumption by 1997, and it was not correlated with
abundance of seeds in the environment. Pre-dispersal seed loss also was estimated in two flowering seasons by counting the
numbers of seeds consumed prior to release from the plant, and was relatively low (<15%). No differences were detected among
the four study sites in patterns of pre-dispersal loss. Field surveys were done at two sites to identify potential seed predators.
Three of the most abundant species identified in these surveys were tested in the laboratory to determine size-specific patterns
of feeding activity and to assess which early life stages of P. torreyi (fruits within spadices, dehisced fruits, seedlings) were most vulnerable to predation. All three of the early life stages
were consumed. The crabs Pugettiaproducta (Randall) and Pachygrapsus crassipes Randall were much more voracious predators than the isopod Idotea resecata Stimpson.
Received: 8 June 1999 / Accepted: 2 February 2000 相似文献
6.
Emerging Tools for Continuous Nutrient Monitoring Networks: Sensors Advancing Science and Water Resources Protection 下载免费PDF全文
Brian A. Pellerin Beth A. Stauffer Dwane A. Young Daniel J. Sullivan Suzanne B. Bricker Mark R. Walbridge Gerard A. Clyde Jr. Denice M. Shaw 《Journal of the American Water Resources Association》2016,52(4):993-1008
Sensors and enabling technologies are becoming increasingly important tools for water quality monitoring and associated water resource management decisions. In particular, nutrient sensors are of interest because of the well‐known adverse effects of nutrient enrichment on coastal hypoxia, harmful algal blooms, and impacts to human health. Accurate and timely information on nutrient concentrations and loads is integral to strategies designed to minimize risk to humans and manage the underlying drivers of water quality impairment. Using nitrate sensors as the primary example, we highlight the types of applications in freshwater and coastal environments that are likely to benefit from continuous, real‐time nutrient data. The concurrent emergence of new tools to integrate, manage, and share large datasets is critical to the successful use of nutrient sensors and has made it possible for the field of continuous monitoring to rapidly move forward. We highlight several near‐term opportunities for federal agencies, as well as the broader scientific and management community, that will help accelerate sensor development, build and leverage sites within a national network, and develop open data standards and data management protocols that are key to realizing the benefits of a large‐scale, integrated monitoring network. Investing in these opportunities will provide new information to guide management and policies designed to protect and restore our nation's water resources. 相似文献
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Christian Mrz Felipe S. Freitas Johan C. Faust Jasmin A. Godbold Sian F. Henley Allyson C. Tessin Geoffrey D. Abbott Ruth Airs Sandra Arndt David K. A. Barnes Laura J. Grange Neil D. Gray Ian M. Head Katharine R. Hendry Robert G. Hilton Adam J. Reed Saskia Rühl Martin Solan Terri A. Souster Mark A. Stevenson Karen Tait James Ward Stephen Widdicombe 《Ambio》2022,51(2):370
Unprecedented and dramatic transformations are occurring in the Arctic in response to climate change, but academic, public, and political discourse has disproportionately focussed on the most visible and direct aspects of change, including sea ice melt, permafrost thaw, the fate of charismatic megafauna, and the expansion of fisheries. Such narratives disregard the importance of less visible and indirect processes and, in particular, miss the substantive contribution of the shelf seafloor in regulating nutrients and sequestering carbon. Here, we summarise the biogeochemical functioning of the Arctic shelf seafloor before considering how climate change and regional adjustments to human activities may alter its biogeochemical and ecological dynamics, including ecosystem function, carbon burial, or nutrient recycling. We highlight the importance of the Arctic benthic system in mitigating climatic and anthropogenic change and, with a focus on the Barents Sea, offer some observations and our perspectives on future management and policy. 相似文献
8.
Fraser ED Dougill AJ Mabee WE Reed M McAlpine P 《Journal of environmental management》2006,78(2):114-127
The modern environmental management literature stresses the need for community involvement to identify indicators to monitor progress towards sustainable development and environmental management goals. The purpose of this paper is to assess the impact of participatory processes on sustainability indicator identification and environmental management in three disparate case studies. The first is a process of developing partnerships between First Nations communities, environmental groups, and forestry companies to resolve conflicts over forest management in Western Canada. The second describes a situation in Botswana where local pastoral communities worked with development researchers to reduce desertification. The third case study details an on-going government led process of developing sustainability indicators in Guernsey, UK, that was designed to monitor the environmental, social, and economic impacts of changes in the economy. The comparative assessment between case studies allows us to draw three primary conclusions. (1) The identification and collection of sustainability indicators not only provide valuable databases for making management decisions, but the process of engaging people to select indicators also provides an opportunity for community empowerment that conventional development approaches have failed to provide. (2) Multi-stakeholder processes must formally feed into decision-making forums or they risk being viewed as irrelevant by policy-makers and stakeholders. (3) Since ecological boundaries rarely meet up with political jurisdictions, it is necessary to be flexible when choosing the scale at which monitoring and decision-making occurs. This requires an awareness of major environmental pathways that run through landscapes to understand how seemingly remote areas may be connected in ways that are not immediately apparent. 相似文献
9.
Dredged material levees in coastal Louisiana are normally associated with pipeline canals or, more frequently, canals dredged
through the wetlands to allow access to drilling locations for mineral extraction. The hydrologic impact on marshes behind
the levee is of concern to coastal resource managers because of the potential impact on sediment transport and deposition,
and the effect on estuarine organism access to valuable nursery habitat. This study examined the effects of gaps in dredged
material levees, compared to continuous levees and natural channel banks, on these two aspects of marsh function. Field studies
for sediment deposition were conducted biweekly for a year, and nekton samples were collected in spring and fall. Variation
in nekton density among study arears and landscape types was great in part because of the inherent sampling gear issues and
in part because of differences in characteristics among areas. Nekton densities were generally greater in natural compared
to leveed and gapped landscapes. Differences in landscape type did not explain patterns in sediment deposition. The gaps examined
appear to be too restrictive of marsh flooding to provide efficient movements of floodwaters onto the marsh during moderate
flooding events. The “trapping” effect of the levees increases sediment deposition during extreme events. Gapping material
levees may be an effective method of partially restoring upper marsh connection to nekton, but this method may work best in
lower elevation marshes where nekton use is greater. 相似文献
10.
Jacob Carstensen Daniel J. Conley Erik Bonsdorff Bo G. Gustafsson Susanna Hietanen Urzsula Janas Tom Jilbert Alexey Maximov Alf Norkko Joanna Norkko Daniel C. Reed Caroline P. Slomp Karen Timmermann Maren Voss 《Ambio》2014,43(1):26-36
Hypoxia has occurred intermittently over the Holocene in the Baltic Sea, but the recent expansion from less than 10 000 km2 before 1950 to >60 000 km2 since 2000 is mainly caused by enhanced nutrient inputs from land and atmosphere. With worsening hypoxia, the role of sediments changes from nitrogen removal to nitrogen release as ammonium. At present, denitrification in the water column and sediments is equally important. Phosphorus is currently buried in sediments mainly in organic form, with an additional contribution of reduced Fe-phosphate minerals in the deep anoxic basins. Upon the transition to oxic conditions, a significant proportion of the organic phosphorus will be remineralized, with the phosphorus then being bound to iron oxides. This iron-oxide bound phosphorus is readily released to the water column upon the onset of hypoxia again. Important ecosystems services carried out by the benthic fauna, including biogeochemical feedback-loops and biomass production, are also lost with hypoxia. The results provide quantitative knowledge of nutrient release and recycling processes under various environmental conditions in support of decision support tools underlying the Baltic Sea Action Plan. 相似文献