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This article reviews historical changes in the total phosphorus (TP) inputs to Loch Leven, Scotland, UK. Data derived from
palaeolimnological records suggest that inputs in the early 1900s were about 6 t TP year−1 (0.45 g TP m−2 year−1). By 1985, this had risen to about 20 t TP year−1 (1.5 g TP m−2 year−1) due to increases in runoff from agricultural land and discharges from point sources. By the late 1970s, increased TP inputs
were causing serious degradation of lake water quality. Most noticeably, there had been an increase in cyanobacterial blooms.
A catchment management plan was implemented in the early 1990s. This resulted in a 60% reduction in the annual TP input between
1985 (20 t TP year−1/1.5 g TP m−2 year−1) and 1995 (8 t TP year−1/0.6 g TP m−2 year−1). The main reduction was associated with better control of point source discharges, but attempts were also made to reduce
inputs from diffuse sources. The reduction in external TP loading to the lake led to a marked decline in TP retention by the
lake each year. 相似文献
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Julie Corden Wendy Millington John Bailey Marion Brookes Eric Caulton Jean Emberlin John Mullins Caroline Simpson Andrew Wood 《Aerobiologia》2000,16(2):227-232
Betula pollen is known to be an importantaeroallergen in Europe and the UK, with very largequantities of pollen released into the air at theheight of the season, making it the most abundant treepollen present in the UK spring air.There has been long term pollen monitoring in Cardiff,Derby and London but in recent years the number ofregional sites has increased.Seven sites throughout the UK have monitoredBetula pollen using Burkard samplers for the period1993–1997 and for this study regionaldifferences in Betula pollen and climate wereinvestigated.Detailed analysis revealed considerable variation inthe start dates, duration and quantityof Betula pollen for the seven UK sitesthroughout the five year period.These regional variations in Betula pollenduration and intensity of season, indicate theimportance of maintaining sites throughout the UK asan aid to clinicians, researchers and the generalpublic. 相似文献
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《Chronobiology international》2013,30(5):1013-1030
The impact on health and safety of the combination of chronic sleep deficits and extended working hours has received worldwide attention. Using the National Health Interview Survey (NHIS), an in-person household survey using a multistage, stratified, clustered sample design representing the US civilian, non-institutionalized population, the authors estimated the effect of total daily self-reported sleep time and weekly working hours on the risk of a work-related injury. During the survey period 2004–2008, 177,576 persons (ages 18–74) sampled within households reported that they worked at a paid job the previous week and reported their total weekly work hours. A randomly selected adult in each household (n?=?75,718) was asked to report his/her usual (average) total daily sleep hours the prior week; complete responses were obtained for 74,415 (98.3%) workers. Weighted annualized work-related injury rates were then estimated across a priori defined categories of both average total daily sleep hours and weekly working hours. To account for the complex sampling design, weighted multiple logistic regression was used to independently estimate the risk of a work-related injury for categories of usual daily sleep duration and weekly working hours, controlling for important covariates and potential confounders of age, sex, race/ethnicity, education, type of pay, industry, occupation (proxy for job risk), body mass index, and the interaction between sleep duration and work hours. Based on the inclusion criteria, there were an estimated 129,950,376 workers annually at risk and 3,634,446 work-related medically treated injury episodes (overall injury rate 2.80/100 workers). Unadjusted annualized injury rates/100 workers across weekly work hours were 2.03 (≤20 h), 3.01 (20–30 h), 2.45 (31–40 h), 3.45 (40–50 h), 3.71 (50–60 h), and 4.34 (>60 h). With regards to self-reported daily sleep time, the estimated annualized injury rates/100 workers were 7.89 (<5 h sleep), 5.21 (5–5.9 h), 3.62 (6–6.9 h), 2.27 (7–7.9 h), 2.50 (8–8.9 h), 2.22 (9–9.9 h), and 4.72 (>10 h). After controlling for weekly work hours, and aforementioned covariates, significant increases in risk/1 h decrease were observed for several sleep categories. Using 7–7.9 h sleep as reference, the adjusted injury risk (odds ratio [OR] for a worker sleeping a total of <5 h/day was 2.65 (95% confidence interval [CI]: 1.57–4.47), for 5–5.9 h 1.79 (95% CI: 1.22–2.62), and for 6–6.9 h 1.40 (95% CI: 1.10–1.79). No other usual sleep duration categories were significantly different than the reference; however, for >10 h of usual daily sleep, the OR was marginally significantly elevated, 1.82 (95% CI: 0.96–3.47). These results suggest significant increases in work-related injury risk with decreasing usual daily self-reported sleep hours and increasing weekly work hours, independent of industry, occupation, type of pay, sex, age, education, and body mass (Author correspondence: david. lombardi@libertymutual. com) 相似文献
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Alan Paine 《Biomarkers》2013,18(3):203-205
As part of a programme to develop biomarker assays for polycyclic aromatic hydrocarbons (PAHs) in marine invertebrates, two species of crabs, Carcinus maenas and Carcinus aestuarii were exposed to benzo(a)pyrene (B(a)P) or crude oil. Microsomes were prepared from the midgut gland (hepatopancreas), examined by gel electrophoresis and Western blotting and assayed for B(a)P monooxygenase activity. In early experiments there was evidence of protein degradation and results were inconsistent and inconclusive. However, when steps were taken to minimize this in subsequent experiments, including the inclusion of four protease inhibitors in the homogenization buffer, there was consistent evidence for an increase of proteins of estimated molecular weight 45-60 kDa, and particularly of a distinct band at c. 48 kDa, following exposure to PAH at levels down to 0.1 ppm in ambient water. In C. aestuarii the increase in this band was found to coincide with an 8-12-fold increaseof B(a)P monooxygenase activity in midgut gland microsomes. These results suggest that one or more forms of cytochrome P450 may be induced by PAHs in these species. However, Western blotting using antibodies raised to vertebrate P450s, and representing four different gene families, failed to recognize any proteins in either the PAH-treated samples or in the controls. The isolation and characterization of induced protein, and the production of antibodies may provide the basis for a biomarker assay to measure a response to environmental PAHs in crabs. 相似文献
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Jhillu Singh Yadav Kamani Satyanarayana Pamu Sreedhar Pabbaraja Srihari Thokhir Basha Shaik Shasi Vardhan Kalivendi 《Bioorganic & medicinal chemistry letters》2010,20(12):3814-3817
The racemic total synthesis of elegansidiol, farnesiferol B, and farnesiferol D has been obtained following a Diels–Alder approach. Gillman addition, cross metathesis reaction are the other key steps involved in the target synthesis. 相似文献
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Siveter DJ Sutton MD Briggs DE Siveter DJ 《Proceedings. Biological sciences / The Royal Society》2007,274(1622):2099-2107
A new arthropod with three-dimensionally preserved soft parts, Tanazios dokeron, is described from the Wenlock Series (Silurian) of Herefordshire, England, UK. Serial grinding, digital photographic and computer rendering techniques yielded 'virtual fossils' in the round for study. The body tagmata of T. dokeron comprise a head shield and a long trunk. The head shield bears six pairs of horn-like spines and the head bears five pairs of appendages. The antennule, antenna and mandible are all uniramous, and the mandible includes a gnathobasic coxa. Appendages four and five are biramous and similar to those of the trunk: each comprises a limb base with an endite, an enditic membrane, and two epipodites, plus an endopod and exopod. The hypostome bears a large cone-like projection centrally, and there may be a short labrum. The trunk has some 64 segments and at least 60 appendage pairs. A very small telson has the anus sited ventrally in its posterior part and also bears a caudal furca. Comparative morphological and cladistic analyses of T. dokeron indicate a crustacean affinity, with a probable position in the eucrustacean stem group. As such the epipodites in T. dokeron are the first recorded in a eucrustacean stem taxon. The new species is interpreted as a benthic or nektobenthic scavenger. 相似文献
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The number of species in the freshwater mussel genus Cristaria Schumacher, 1817 recognized from Far East Russia has varied over the last several decades. While some authors consider the occurrence of only one species, Cristaria plicata (Leach, 1815), widespread in East Asia, others, recognize two separate species Cristaria herculea (Middendorff, 1847) and Cristaria tuberculata Schumacher, 1817 from Far East Russia, distinct from C. plicata. For the present study, freshwater mussels, identified as C. herculea, were collected in the Upper Amur basin (Transbaikalia, Russia). The shell morphology and the whole soft body anatomy were analysed in detail and compared with previously published information on other Cristaria spp.. Additionally, a cytochrome oxidase subunit 1 (CO1) gene fragment was sequenced from foot tissue samples of selected animals, collected from the same region, and compared with published data. Based upon morphological similarities of glochidia and adult morphology and anatomy as well as the mitochondrial DNA sequence analysis, we consider C. herculea as a synonym of C. plicata. Further analysis of Far East Russia C. herculea and C. tuberculata specimens using both molecular and morphological characters should be carried in the future to enhance our knowledge about the taxonomy within the Cristaria genus. Moreover, a comprehensive revision of the genus Cristaria is needed, restricting the type locality and comparing topotypic specimens for both C. plicata and C. tuberculata, and including all recognized Cristaria species. 相似文献
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Male karyotype and meiosis of Tenagobia fuscata (Corixoidea, Micronectidae) are studied. The species possesses a male diploid chromosome number 2n = 28 + XY, holokinetic chromosomes, absence of m chromosomes and an achiasmatic male meiosis. Autosomes divide pre-reductionally while the sex chromosomes do so post-reductionally. Banding techniques (C, DAPI and CMA) show that large heterochromatic AT-GC rich bands are generally terminally located, although some interstitial bands are also detected. Many bivalents are heteromorphic for heterochromatin amount and location. This is the first report of a species with achiasmatic male meiosis within the Nepomorpha. These cytogenetic features markedly differ from all previous reports for 26 species of the superfamily Corixoidea. T. fuscata occurs in permanent shallow water bodies, and most known individuals are brachypterous. Their dispersion depends on occasional floodings of the water bodies they occupy. Since achiasmatic meiosis maintains groups of co-adapted genes, this feature could be an adaptive strategy of the species to the particular type of habitat and ecological niche it occupies. 相似文献