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51.
Concern about the environmental effect of air pollution on areas of high conservation value in the UK has prompted the statutory agencies to initiate an investigation on these areas. For this, critical loads maps have been used together with predicted air pollution data, monitored air pollution data and remotely sensed land cover information within a geographic information system (GIS). Additional information on designated Sites of Special Scientific Interest (SSSI) for England and Wales have also been incorporated. This provides the framework for examining potential impacts to these sites under various current and future scenarios. The approach allows for the investigation of the impacts of individual point sources as well as complete national scenarios. Preliminary results are provided from analysis of a single pollutant (sulphur). These indicate that nationally up to 52% of the area of SSSI's (5000 km2) are at risk from soil acidification. Using this approach it has been possible to apportion the load on any SSSI, thereby enabling the ecological impacts of each point source to be identified. This information can then be used to assess priorities for regulatory controls.  相似文献   
52.
An adequate calcium intake during the first years of life is needed for normal growth and development and to prevent rickets. The bioavailability of calcium from infant foods (milk-based formulas and fruit juices containing milk and cereals, FMC), the dietary sources of calcium in these stages of life, has been estimated on the basis of simulated gastrointestinal digestion and calcium solubility and dialyzability values and on the efficiency of transport and uptake by Caco-2 cells. The ranking of samples according to calcium bioavailability depends on the use of solubility or dialyzability as criterion. On the basis of the former, the highest value corresponded to adapted formulas and the lowest to fruit juices. However, when using percentage dialysis, the highest value corresponded to fruit juices and the lowest to follow-up formulas. The highest percentages of transport efficiency and uptake by Caco-2 cells corresponded to calcium from the analyzed fruit juices, followed by toddler, follow-up, and adapted formulas.  相似文献   
53.
The roles of sulphur (S) and nitrogen (N) in causing critical loads exceedance across the UK show considerable spatial variability at the present time. Over much of lowland Britain it appears that the environment can only be protected by reducing N deposition, whilst in upland areas (e.g. most of Scotland and Wales) reductions in S deposition are the primary requirement. Using the Hull Acid Rain Model (HARM) the effects of current and possible future emissions control legislation on critical loads exceedance can be explored. Based on HARM output, the implementation of the UNECE Sulphur Protocol (1994) will bring about a substantial reduction in the amount of S being deposited in the UK, especially in central and southern parts of the country. Some areas will remain where additional reductions in S are required. Over most of the country, however, the need to reduce N deposition will become paramount. The changing contributions and significance of non-UK sources can be estimated.  相似文献   
54.
The olive tree had been domesticated during the early Neolithic in the Near East, and more than 1000 different cultivars have been identified to date. However, examples of wild olive trees (Olea europaea oleaster) can still be found in the Mediterranean basin. Evidence of oleaster use for oil production can be found in historical and sacred texts, such as the Odyssey, the Holey Koran, and the Holey Bible. While the nutritional and healthful properties of olive oil are actively being explored, there are no data on the human actions of oleaster oil. Therefore, we investigated the effect of prolonged, i.e., 1 month, consumption of oleaster oil on the lipid profile of a 40 healthy Algerian subjects (aged 27.9 ± 3.85 years), as compared to nonconsumers from the same area. Plasma urea, creatinine, and uric acid concentrations and glycemia did not significantly differ, at the end of the study, between controls and oleaster-oil-supplemented subjects. Conversely, we recorded significant decreases of plasma triglyceride concentration (-24.8%; p < 0.05), total cholesterol (-12.13%; p < 0.05), and low-density lipoprotein-cholesterol (LDL-C) (-24.39%; p < 0.05) in oleaster-oil-treated subjects. Concomitantly, high-density lipoprotein-cholesterol (HDL-C) concentrations were significantly increased (17.94%; p < 0.05) by oleaster oil administration. In conclusion, we show that oil obtained from feral olive trees, i.e., oleasters, improves the plasma lipid profile of healthy volunteers.  相似文献   
55.
Necrotic enteritis (NE) is an important enteric disease in poultry and has become a major concern in poultry production in the post-antibiotic era. The infection with NE can damage the intestinal mucosa of the birds leading to impaired health and, thus, productivity. To gain a better understanding of how NE impacts the gut function of infected broilers, global mRNA sequencing (RNA-seq) was performed in the jejunum tissue of NE challenged and non-challenged broilers to identify the pathways and genes affected by this disease. Briefly, to induce NE, birds in the challenge group were inoculated with 1 mL of Eimeria species on day 9 followed by 1 mL of approximately 108 CFU/mL of a NetB producing Clostridium perfringens on days 14 and 15. On day 16, 2 birds in each treatment were randomly selected and euthanized and the whole intestinal tract was evaluated for lesion scores. Duodenum tissue samples from one of the euthanized birds of each replicate (n = 4) was used for histology, and the jejunum tissue for RNA extraction. RNA-seq analysis was performed with an Illumina RNA HiSeq 2000 sequencer. The differentially expressed genes (DEG) were identified and functional analysis was performed in DAVID to find protein–protein interactions (PPI). At a false discovery rate threshold <0.05, a total of 377 DEG (207 upregulated and 170 downregulated) DEG were identified. Pathway enrichment analysis revealed that DEG were considerably enriched in peroxisome proliferator-activated receptors (PPAR) signaling (P < 0.01) and β-oxidation pathways (P < 0.05). The DEG were mostly related to fatty acid metabolism and degradation (cluster of differentiation 36 [CD36], acyl-CoA synthetase bubblegum family member-1 [ACSBG1], fatty acid-binding protein-1 and -2 [FABP1] and [FABP2]; and acyl-coenzyme A synthetase-1 [ACSL1]), bile acid production and transportation (acyl-CoA oxidase-2 [ACOX2], apical sodium–bile acid transporter [ASBT]) and essential genes in the immune system (interferon-, [IFN-γ], LCK proto-oncogene, Src family tyrosine kinase [LCK], zeta chain of T cell receptor associated protein kinase 70 kDa [ZAP70], and aconitate decarboxylase 1 [ACOD1]). Our data revealed that pathways related to fatty acid digestion were significantly compromised which thereby could have affected metabolic and immune responses in NE infected birds.  相似文献   
56.
Plankton community structure and chlorophyll a concentration were compared in twelve 0.1 ha earthen ponds co‐stocked with channel catfish (Ictalurus punctatus Rafinesque, 1818) in a multiple‐batch culture (initial biomass=5458 kg ha?1) and a planktivore, threadfin shad (Dorosoma petenense Güther, 1867; initial biomass=449 kg ha?1), during the April–November growing season. We used a completely randomized design in a 2 × 2 factorial arrangement to test the planktivore level (presence or absence of threadfin shad) and channel catfish feeding frequency (daily or every third day). Channel catfish were fed a 32% protein feed to apparent satiation on days fed. The presence of threadfin shad affected phytoplankton and zooplankton community structure more than did feeding frequency, and the impact in ponds was more pronounced after 1 July. The numbers of all major groups of zooplankton were lower in ponds with threadfin shad, but were unaffected by the feeding frequency. Chlorophyll a concentration before 1 July was higher in ponds with threadfin shad and unaffected by the feeding frequency, whereas after 1 July it was higher in ponds without threadfin shad and that were fed daily. Phytoplankton community structure after 1 July was dominated by nuisance algal bloom genera of cyanobacteria in ponds without threadfin shad and by Bacillariophyceae in ponds with threadfin shad.  相似文献   
57.
Biological indicators based on abundances of soil organisms are powerful tools for inferring functional and diversity changes in soils affected by agricultural perturbations. Field plots, combining organic and conventional practices with no tillage, conservation tillage and standard tillage maintained different nematode assemblages and soil food webs. Soil food web indices based on nematode assemblages were reliable predictors of the trophic composition of functional characteristics of soil mite assemblages. Bacterial-feeding and predatory nematodes, together with predatory mites, were abundant in the organic-no till treatments and were associated with high values of the Enrichment and the Structure Index based on nematode assemblages. Conventional-Standard tillage treatments had high abundances of fungal- and plant-feeding nematodes and algivorous mites, associated with high values of the Basal and Channel Index. This study validates the hypothesis that nematode-based soil food web indices are useful indicators of other soil organisms such as mites, with similar functional roles and environmental sensitivities.  相似文献   
58.
Sharp-crested weirs are the simplest form of over-flow spillway that commonly used to determine the flow rate in hydraulic laboratories, industry and irrigation systems, where highly accurate discharge measurements are needed. In this study, the experimental upper and lower nappe profiles in rectangular sharp-crested weirs are fitted by quadratic and cubic equations, respectively. In addition, free-vortex theory is used to simulate flow over this kind of weirs and determine discharge coefficient. Physical models of sharp-crested weirs with various widths and heights were considered. The proposed method agrees well with the experimental observations. Also, the experimental data indicate that the suggested equation presents reasonable results for the range of 0 < h/P < 9.  相似文献   
59.
60.
Chlorpyrifos (Dowco 179) and its dimethyl homologue, chlorpyrifosmethyl (Dowco 214), were used to study the influence of the O,O-dialkyl group of organophosphorus insecticides on toxicity, absorption, and metabolism among larvae of the tobacco budworm [Heliothis virescens (F.)] from strains that were resistant (R) and susceptible (S) to methyl parathion. In toxicity tests, chlorpyrifos and chlorpyrifosmethyl were more toxic than methyl parathion to 3rd-stage R larvae but less toxic to S larvae. Chlorpyrifosmethyl was more toxic (3–4 ×) than chlorpyrifos to both strains of larvae, and the results of absorption studies indicated that the toxicity differential of the homologues may be explained in part by the more rapid absorption of the dimethyl form. Studies of the in vivo metabolism of both Dowco compounds indicated that each was degraded mainly by the cleavage of the pyridylphosphate linkage. In vitro tests demonstrated that the NADPH-dependent microsomal oxidases were of primary importance in detoxification, while glutathione (GSH)-dependent mechanisms (aryl- and alkyltransferases) present in the soluble cell fractions were of lesser importance. O-dealkylation occurred only with chlorpyrifosmethyl. The R larvae demonstrated greater capability in detoxifying both compounds in the comparative in vivo and in vitro studies of metabolism, but the differences were more apparent during the 5th instar than during the 3rd instar.  相似文献   
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