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Arsenic occurs as a persistent constituent in many of the chemical weapons dumped into the Baltic Sea; it can be used as an indicator of leakage and dispersal of released munitions to the marine environment. Total arsenic was analysed in sediment samples taken from the Lithuanian economic zone in the Baltic Sea, which included samples from the chemical munitions dumpsite in the Gotland Basin and national monitoring stations in the southeastern Baltic Sea. Arsenic concentrations in sediments ranged from 1.1 to 19.0 mg kg(-1), with an average of 3.4 mg kg(-1). Although there was evidence of slightly elevated arsenic content in sediments near the weapons dumpsite, arsenic concentrations were nevertheless quite low relative to other investigations in the Baltic and North Seas.  相似文献   
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Gene flow from crop fields to wild populations produces hybrids that often differ from their wild counterparts in growth form, phenology, and life history characteristics. Germination and dormancy dynamics have a strong influence on population persistence, competitive dynamics, and ultimately, plant fitness. They may also play a role in modifying crop gene introgression, which has been of primary interest since the release of transgenic crops. We investigated how seed germination and dormancy were affected by sunflower crop wild hybridization in both laboratory and field experiments. Hybridization increased seed germination and decreased dormancy. Of the nine wild populations we assayed, most of their hybrids had higher germination than the wilds of the same population. However, absolute germination levels varied by population and testing environment. Hybrids produced by three different crop lines differed in germination, and their germination rankings shifted across populations. Increased germination in hybrids could accelerate crop gene introgression, provided that hybrids germinate in an appropriate period. Differences in relative germination of wild and hybrid seed indicated that the effect of germination on introgression will likely vary by population due, in part, to initial levels of dormancy in the population. Therefore, the implications of gene flow from crops with novel characteristics or from transgenic crops will also vary by population.  相似文献   
3.
An estuarine sediment sample, IAEA-405, was recently characterised for trace elements and methylmercury (MeHg) for ultimate use as a marine reference material. The reference values were calculated using data sets from 120 laboratories that participated in a world-wide intercomparison exercise. The data evaluation is highlighted, and includes comparisons of different analytical methods, as well as the distribution of data. Overall laboratory performance for this exercise was encouraging: 86 laboratories (72%) reported data with <25% outliers. There was sufficient acceptable data to establish recommended values for 17 elements and information values for a further 15 elements. In addition, a recommended value was established for methylmercury. The estuarine sediment sample, IAEA-405, can be used as a reference material for quality control in the determination of trace elements and methylmercury in moderately polluted sediments.  相似文献   
4.
ABSTRACT

“Community energy” (CE) is argued to be an opportunity to transition to low-carbon energy systems while creating additional benefits for local communities. CE is defined as energy initiatives that place a high degree of emphasis on participation of local community members through ownership and control, where through doing so, benefits are created for the community. The trend has seen considerable growth in many countries over the last decade. Occurring simultaneously is a trend for local communities (e.g. municipalities) to create their own Local Energy Plans (LEPs) – a planning process that articulates energy-related actions (i.e. expected outcomes). While CE and LEPs both address energy activities in a local context, any further connection between these trends remains unclear.

This research develops a framework, based on CE and LEP literature, to assess LEPs for their relevance to CE. The research analyses 77 LEPs from across Canada for the ways in which they address the three components that define CE: community participation, community ownership, and community capacity. The main findings are that LEPs have emerged as a process that is both relevant to CE and capable of strategically addressing its components. Despite this, LEPs do not appear to reveal a radically different approach to the “closed and institutional” models of traditional community involvement practices. The investigation suggests that for CE advocates, LEPs may be considered to be an important avenue to pursue CE ambitions. LEPs could increase their relevance to CE by improving the processes and actions related to all three CE components.  相似文献   
5.
The aim was to assess the role that fetal bladder size has in the determination of fetal hydronephrosis. Forty-three fetuses were evaluated for fetal hydronephrosis in the second trimester of pregnancy. Anteroposterior measurements of the renal pelvis were obtained with a full bladder and again when the bladder emptied in each fetus. Statistical analysis was performed using the Spearman rank order correlation coefficient to assess the relationship between bladder status and renal dilation. The anteroposterior size of the fetal renal pelvis diminished from 6.8 ± 1.8 mm on a full bladder scan to 4.5 ± 1.6 mm when the bladder was emptied (P<0.001). Fifty-three per cent of the fetuses whose renal pelvic measurements were 5 mm or more on a full bladder scan had normal-appearing renal pelvises when their bladders emptied. The status of the fetal bladder should be considered when evaluating fetal hydronephrosis.  相似文献   
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