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John Boardman 《Journal of Soils and Sediments》2013,13(9):1636-1644
Purpose
Roads in general and sunken lanes (SLs) in particular play an important hydrological role in connecting areas of runoff and sediment generation with valley floors and therefore with habitation and watercourses. These connections lead to damage and pollution. The role of SLs has been neglected as an important source of runoff and sediment and in hydrological and geomorphological discussion in the literature on connectivity.Materials and methods
Published data on the role of roads and specifically SLs are reviewed. Fluxes of runoff and sediment have been mapped in a study area during a period of serious erosion (2006–2007). Routes to watercourses and entry points to a vulnerable river are recorded.Results and discussion
SLs are historic features often hundreds of years old. Unmetalled SLs continue to incise whereas metalled ones generally act as routes for runoff and sediment with inputs from many sources. These include field gateways, other SLs, tracks and trails (some metalled, some unmetalled), bank gullies and mass movements on SL banks, burrows and pipes in banks, and erosion of roadside verges. The proportion of sediments from these sources is unknown and area specific. Impacts and costs include muddy flooding of villages, road clearance and ecological damage to rivers due to pollution and sedimentation.Conclusions
The location of SLs is influenced by two factors: long-term human occupation of the landscape and soft, easily eroded geology. They are an important element in the connectivity between hillslopes and valley bottoms. They play a role in the muddy flooding of villages and increased sedimentation in rivers in areas such as Flanders, the Polish Carpathians and the study area in southern England. 相似文献3.
《Biological conservation》1986,36(2):143-158
The Dutch chalk grasslands were formerly very rich in bryophyte and lichen species. A comparison of data from Barkman (1953) and more recent inventories yielded the following results: (a) Lichens have disappeared nearly completely from the Dutch chalk grasslands; (b) Many characteristic acrocarps (e.g., Tortella spp., Trichostomum spp., Aloina spp., Pleurochaete squarrosa) and some pleurocarps (Abietinella abietina, Camptothecium lutescens) have decreased drastically; (c) Some common litter-indicator species (Brachythecium rutabulum and others) are now increasing.We hypothesise that this change is mainly a result of combined effects of the abandonment of the old grazing regime, which is in only a few places replaced by mowing, and of air pollution. We are strongly in favour of current attempts to reintroduce grazing by the old race of ‘Mergelland’ sheep. 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(13-14):2355-2369
Abstract An investigation was conducted to determine the nature of decomposition products resulting from the interaction between humic acid and apatite and assess their availability to plant growth. Interaction analyses were performed by shaking 200 mg apatite with 0 to 800 mg/L HA or FA solutions at pH 5 or 7 for 0 to 12 hr. Phosphorus concentrations were determined in the supernatants by spectrophotometry. The nature of P‐humic acid complexes was determined by 31P NMR analysis. Availability of these dissolution products was studied by growing corn plants in aerated hydroponics to which 200 mg apatite and 0 to 800 mg/L HA were added at pH 5 or 7. The results indicated that the rate of dissolution of apatite was parabolic in regression with time, and increased by increasing the amounts of HA or FA applied from 100 to 800 mg/L The dissolution reaction was influenced by pH, because larger amounts of PO4 3‐ions were detected at pH 5 than at pH 7. 31P NMR spectroscopy indicated the presence of P‐humic acid complexes, previously believed to be humophosphate esters. The PO4 3‐ ion was complexed by HA at pH 7 or above, but PO4 3‐ appeared to be released again as adsorbed and free ions at pH <5.0. Plant performance corresponded with increased PO4 3‐concentrations at pH 5.0. No significant improvement over the control was observed in the growth of corn plants by apatite + HA treatments at pH 7. However, plant growth was increased significantly over the control by apatite + HA treatments at pH 5.0. Better growth performance of corn plants were noticed by apatite + HA than by KH2PO4 treatments at pH 5.0. 相似文献
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I assessed the direct influence of earthworm excretions, and the impact of earthworms through their action on the soil structure (increased macroporosity), on the population dynamics of the collembolan species Heteromurus nitidus. The intestinal content of Collembola arising from cultures on different soil types was observed, and two experimental cultures of H. nitidus were run: (1) a culture performed on an inert substrate supplied either with earthworm casts or with soil as food resource, (2) an experiment using microcosms with cores of two humus forms (moder and calcic mull), in the presence or absence of earthworms. The observation of gut contents revealed that H. nitidus feeds on excrements, the composition of which (ratio organic matter/mineral matter) varies according to the humus form where it lived. Slightly aged (10–15 days) organo-mineral casts of earthworms appeared to be a better food than calcic mull aggregates or organic material from moder. Densities of H. nitidus cultured in cores of calcic mull were higher than in moder, except when cores of moder were inhabited by an anecic earthworm for 2 months. The humus form strongly influenced populations of H. nitidus, firstly because densities of predators were higher in moder than in calcic mull, and probably also because of soil macroporosity. It was concluded that earthworms would affect predation on H. nitidus by creating a network of interconnected macropores in which Collembola can move and find shelter. 相似文献
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Vaníčková L do Nascimento RR Hoskovec M Ježková Z Břízová R Tomčala A Kalinová B 《Journal of agricultural and food chemistry》2012,60(29):7168-7176
The medfly (Ceratitis capitata) is one of the major agricultural pests controlled through sterile insect technique (SIT) programs. We studied the chemical composition of the volatiles released by calling males from one laboratory and two wild C. capitata populations using two-dimensional gas chromatography with time-of-flight mass spectrometric detection (GC × GC/TOFMS) and gas chromatography with electroantennographic detection (GC-EAD). Multivariate data analyses revealed significant differences in the quantitative and qualitative composition of male chemical emanations between the three populations. The GC-EAD analyses of the male emanation of three C. capitata populations revealed 14 antenally active compounds. The volatiles isomenthone, β-pinene, ethyl octanoate, indole, geraniol, bornyl acetate, geranyl acetone, and (E)-caryophyllene are newly reported EAD active constituents of the male pheromone. GC-EAD analyses of the laboratory population indicated that the males and females of C. capitata possess comparable sensitivity to male-produced volatiles. Our results are relevant to the development of a pheromone-based monitoring system and also to the SIT control program. 相似文献
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David Sánchez-Fernández David T. Bilton Ignacio Ribera Andrés Millán 《Biological conservation》2008,141(6):1612-1627
One of the most serious environmental problems is the current acceleration in the rate of species extinction associated with human activities, which is occurring particularly rapidly in freshwaters. Here we examine whether endemic water beetles are effectively protected by existing conservation measures in the Iberian Peninsula and the Balearic Islands, a region of high diversity and intense human pressure. We used an exhaustive database for aquatic beetles in the region to address such issues. Firstly, we identify the most threatened endemic taxa using a categorization system to rank species according to their conservation priority or vulnerability. Of the 120 endemic species of water beetles used in the analysis, only two (Ochthebius ferroi and Ochthebius javieri) were identified as being extremely vulnerable, 71 were highly vulnerable and 46 moderately vulnerable, with only a single species identified as having low vulnerability status. Since no Iberian species of aquatic Coleoptera has legal protection, the only conservation measure available for these species is the extent to which they occur in protected areas. Here we identify distributional hotspots for threatened endemic species, and evaluate the extent to which these are already included in the Natura 2000 network in Spain and Portugal. Despite a high degree of concordance between hotspots and Natura 2000 sites, the distribution of four species falls completely outside the network. The analysis also reveals that Natura 2000 fails to protect saline water bodies, despite their high conservation interest and narrow global distribution. The picture revealed here with water beetles is likely to be similar for others groups of freshwater macroinvertebrates, since Coleoptera are known to be good surrogates of aquatic biodiversity in the region. Finally, the degree of protection provided via Natura 2000, and the utility of red lists are discussed. 相似文献
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OBJECTIVE: Concordance of nutritional research priorities with the related burden of disease is essential to develop cost-effective interventions to address the nutritional problems of populations. The present study aimed to evaluate whether nutrition research priorities are in agreement with the population's nutritional problems in Latin America. DESIGN: The epidemiological profile was contrasted with the research priorities and research produced by academic institutions for each country. Qualitative analysis of research production by type of contribution to problem solving was also conducted. SETTINGS: Nine Latin American countries. RESULTS: Obesity (high body mass index (BMI)) and micronutrient deficiencies (anaemia) emerged as key problems, followed by stunting, breast-feeding/lactation and low birth weight. Wasting in children and women (low BMI) was uncommon. Concordance of ranked research priorities with the epidemiological profile of the country was generally good for nutrition-related chronic diseases, micronutrients and low birth weight, but not for undernutrition, stunting and breast-feeding. Studies on the efficacy and effectiveness of interventions were uncommon. CONCLUSIONS: The present research agenda insufficiently supports the goal of public health nutrition, which is to ensure the implementation of cost-effective nutrition programmes and policies. A more rational approach to define research priorities is needed. 相似文献
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Vanden Bussche J Kiebooms JA De Clercq N Deceuninck Y Le Bizec B De Brabander HF Vanhaecke L 《Journal of agricultural and food chemistry》2011,59(10):5786-5792
In recent years, questions have been raised on the possible semi-endogenous status of the alleged xenobiotic thyreostatic drug thiouracil; thiouracil has been detected in the urine of various animals (livestock and domesticated) at concentrations between 1 and 10 μg L(-1) and also in human urine. Although several studies suggest Brassicaceae-derived feed as potential origin, no traces of thiouracil have been detected in feed so far. Therefore, the aim of this study was to elucidate the origin of thiouracil in the urine of livestock and humans. To this purpose various Brassicaceae feed and food sources (e.g., rapeseed, rapeseed coarse meal, cabbage, cauliflower, broccoli) were investigated for the presence of thiouracil. In addition, the impact of the Brassicaceae-related β-thioglucosidase enzyme was evaluated. This myrosinase enzyme appeared to be crucial, because without its catalyzed hydrolysis no thiouracil could be detected in the various Brassicaceae-derived samples. Therefore, a sample pretreatment with incorporated enzymatic hydrolysis was developed after ensuring the quality performance of the extracted myrosinase mixture with a single-point glucose assay. Upon enzymatic hydrolysis and LC-MS(2) analysis, thiouracil was successfully detected in samples of traditional rapeseed, rapeseed-'00' variety coarse meal (values of erucic acid <2% and glucosinolates <25 μmol g(-1)), and rapeseed cake at 1.5, 1.6, and 0.4 μg kg(-1), respectively. As for the food samples, broccoli and cauliflower displayed thiouracil concentrations of 6.0 and <1.0 μg kg(-1), respectively. To the best of the authors' knowledge this study is the first to report the presence of naturally occurring thiouracil in feed and food samples. Future research should investigate the pathway of thiouracil formation and identify its possible precursors. 相似文献
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Glaciela Kaschuk Thomas W. Kuyper Mariangela Hungria 《Soil biology & biochemistry》2009,41(6):1233-287
Rhizobial and arbuscular mycorrhizal (AM) symbioses each may consume 4-16% of recently photosynthetically-fixed carbon to maintain their growth, activity and reserves. Rhizobia and AM fungi improve plant photosynthesis through N and P acquisition, but increased nutrient uptake by these symbionts does not fully explain observed increases in the rate of photosynthesis of symbiotic plants. In this paper, we test the hypothesis that carbon sink strength of rhizobial and AM symbioses stimulates the rates of photosynthesis. Nutrient-independent effects of rhizobial and AM symbioses result in direct compensation of C costs at the source. We calculated the response ratios of photosynthesis and nutrient mass fraction in the leaves of legumes inoculated with rhizobial and/or AM fungi relative to non-inoculated plants in a number of published studies. On average, photosynthetic rates were significantly increased by 28 and 14% due to rhizobial and AM symbioses, respectively, and 51% due to dual symbiosis. The leaf P mass fraction was increased significantly by 13% due to rhizobial symbioses. Although the increases were not significant, AM symbioses increased leaf P mass fraction by 6% and dual symbioses by 41%. The leaf N mass fraction was not significantly affected by any of the rhizobial, AM and dual symbioses. The rate of photosynthesis increased substantially more than the C costs of the rhizobial and AM symbioses. The inoculation of legumes with rhizobia and/or AM fungi, which resulted in sink stimulation of photosynthesis, improved the photosynthetic nutrient use efficiency and the proportion of seed yield in relation to the total plant biomass (harvest index). Sink stimulation represent an adaptation mechanism that allows legumes to take advantage of nutrient supply from their microsymbionts without compromising the total amount of photosynthates available for plant growth. 相似文献
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In the mid-1990s, anecdotal reports of Olympic marmot (Marmota olympus) disappearances from historically occupied locations suggested that the species might be declining. Concern was heightened by the precipitous decline of the Vancouver Island marmot (Marmota vancouverensis), coupled with reports that climate change was affecting other high-elevation species. However, it was unclear whether the Olympic marmot was declining or undergoing natural extinctions and recolonizations; distinguishing between normal metapopulation processes and population declines in naturally fragmented species can be difficult. From 2002-2006, we used multiple approaches to evaluate the population status of the Olympic marmot. We surveyed sites for which there were records indicating regular occupancy in the later half of the 20th century and we conducted range-wide surveys of open high-elevation habitat to establish current and recent distribution. We used these targeted and general habitat surveys to identify locations and regions that have undergone extinctions or colonizations in the past 1-4 decades. Simultaneously, we conducted detailed demographic studies, using marked and radio-tagged marmots, to estimate the observed and projected current population growth rate at nine locations. The habitat surveys indicate that local extinctions have been wide-spread, while no recolonizations were detected. Abundance at most intensive study sites declined from 2002-2006 and the demographic data indicate that these local declines are ongoing. Adult female survival in particular is considerably lower than it was historically. The spatial pattern of the extinctions is inconsistent with observed metapopulation dynamics in other marmot species and, together with very low observed dispersal rates, indicates that population is not at equilibrium. 相似文献
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O'Kane G 《Public health nutrition》2012,15(2):268-276
The current, globalised food system supplies 'cheap' food to a large proportion of the world's population, but with significant social, environmental and health costs that are poorly understood. The present paper examines the nature and extent of these costs for both rural and urban communities, by illustrating the financial pressures on food producers and manufacturers to produce cheap food, the disconnection people experience with how and where their food is produced, and the rise in obesity levels that plague the globe. The paper then proposes that community food systems may play an important role in mitigating the adverse environmental, economic and social effects of the dominant food system, by the use of more sustainable food production methods, the development of local economies and enabling closer connections between farmers and consumers. There are many opportunities for public health nutritionists to contribute to the local food system literature to ascertain whether these systems improve inequities, provide better access to healthy food and help stem the tide of rising global obesity levels. Public health nutritionists can play a key role in supporting people to become food citizens and to advocate for democratic and sustainable food systems. 相似文献
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An environmentally friendly protein fractionation process using supercritical carbon dioxide (SCO(2)) as an acid was developed to produce enriched α-lactalbumin (α-LA) and β-lactoglobulin (β-LG) fractions from whey protein isolate solutions containing from 2 to 10% WPI. This study investigated the effects of pH, temperature, WPI concentration, and residence time on the precipitation kinetics and recovery yields of individual whey proteins and the relative enrichment and composition of both protein fractions. At 5.5-34 MPa and 60-65 °C, solubilized SCO(2) decreased solution pH and induced the formation and precipitation of α-LA aggregates. Gel electrophoresis and HPLC of the enriched fractions demonstrated the production of ≥ 60% pure α-LA, and ≥ 70% pure β-LG, under various operating conditions, from WPI containing ~57% β-LG and 21% α-LA. The enriched fractions are ready-to-use food ingredients with neutral pH, untainted by acids and contaminants. 相似文献
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Marriott LD Robinson SM Poole J Borland SE Godfrey KM Law CM Inskip HM;Southampton Women's Survey Study Group 《Public health nutrition》2008,11(7):751-756
OBJECTIVE: To evaluate the relative validity of a food frequency questionnaire (FFQ) for assessing nutrient intakes in 6-month-old infants. DESIGN AND SETTING: The FFQ was developed to assess the diets of infants born to women in the Southampton Women's Survey (SWS), a population-based survey of young women and their offspring. The energy and nutrient intakes obtained from an interviewer-administered FFQ were compared with those obtained from a 4-day weighed diary. SUBJECTS AND METHODS: A sub-sample of 50 infants aged 6 months from the SWS had their diets assessed by both methods. The FFQ recorded the frequencies and amounts of milks, baby foods, regular foods and drinks consumed by the infants over the previous seven days. The diaries recorded the weights of all foods and drinks consumed by the infants on four separate days within 15 days following FFQ completion. RESULTS: Spearman rank correlation coefficients for intakes of energy, macronutrients and 18 micronutrients, determined by the two methods, ranged from r = 0.39 to 0.86; adjustment for energy intake tended to increase the correlation coefficients, range r(a) = 0.55 to 0.89. Bland-Altman statistics showed that mean differences between methods were in the range of -12.5% to +12.5% except for vitamin B12 (-18.9%). CONCLUSION: Although there were differences in absolute energy and nutrient intakes between methods, Spearman rank correlation coefficients indicated reasonable agreement in the ranking of intakes. The interviewer-administered FFQ is a useful tool for assessing energy and nutrient intakes of healthy infants aged about 6 months. 相似文献
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H. I. Shuval 《Water, air, and soil pollution》2000,123(1-4):605-630
Are the conflicts over water resources between Syria, Lebanon and Israel who share the transboundary waters of the Jordan River Basin a major obstacle to the peace process? The Syrians and Lebanese have in the past claimed as their own all of the sources of the Jordan River which arise in their territory. International water law provides a strong legal basis to assure the water rights and continued use of water by a downstream riparian, such as Syria's use of the Euphrates which arises in Turkey and similarly, Israel's use of the Jordan River, based on prior use in an international river basin. This paper will evaluate the water security implications for Israel of a possible peace agreement with Syria and Lebanon which would involve Israel forgoing the continued use of those amounts of water from the Jordan River that were approved by the Israel Government under the so-called Johnston Plan of 1956 — 35 million m3/yr. for Lebanon from the Hasbani Springs and 42 mm3/yr. from the Banias Springs and Jordan River for Syria. The maximum replacement cost for that amount of water by desalination of seawater may be about $0.70/m3 or, some $56,000,000 per year. This is not a great amount of money as part of the price for peace. The paper also shows that Israel does not have to hold on to the entire area of the Golan Heights to assure its water security and that a 1–3 km water security zone along the Syrian side of the international border under joint and international inspection can be an effective water security measure to assure inspection, monitoring and control of all the sources of the Jordan River and Lake Kinneret vital to Israel's water security. The scare stories published by some groups in Israel, that Syria could, after a peace agreement is signed, covertly divert essentially all of Israel's water resources derived from the sources of the Jordan River or 30% of the country's water supply are highly unrealistic. Such major works could not go undetected and Syria and the world recognize that such an act would be viewed as a causus belli and as an act of war by Israel. In an era of peace, development of the shared water resources of the Jordan and continuous water systems in a program of regional cooperation can bring benefits to all of the partners on the Jordan River Basin. 相似文献
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Savy M Martin-Prével Y Danel P Traissac P Dabiré H Delpeuch F 《Public health nutrition》2008,11(2):132-141
OBJECTIVES: To study dietary diversity and its relationship with socio-economic and nutritional characteristics of women in an urban Sahelian context. DESIGN: A qualitative dietary recall was performed over a 24-h period. Dietary diversity scores (DDS = number of food groups consumed) were calculated from a list of nine food groups (DDS-9) or from a list of 22 food groups (DDS-22) which detailed both micronutrient- and energy-dense foods more extensively. Body mass index (BMI), mid upper-arm circumference and body fat percentage were used to assess the nutritional status of the women. SETTING AND SUBJECTS: Five hundred and fifty-seven women randomly selected in two districts of Ouagadougou, the capital of Burkina Faso. RESULTS: The mean DDS-9 and DDS-22 were 4.9 +/- 1.0 and 6.5 +/- 1.8 food groups, respectively. In the high tertile of DDS-22, more women consumed fatty and sweetened foods, fresh fish, non-fatty meat and vitamin-A-rich fruits and vegetables. The DDS-9 was not associated with the women's socio-economic characteristics whereas the DDS-22 was higher when the women were younger, richer and had received at least a minimum education. Mean BMI of the women was 24.2 +/- 4.9 kg m-2 and 37% of them were overweight or obese (BMI > or = 25 kg m-2). Neither the DDS-9 nor the DDS-22 was associated with the women's anthropometric status, even though there was a trend towards fewer overweight women in the lowest tertile of DDS-22. CONCLUSION: In this urban area, the qualitative measurement of dietary diversity is not sufficient to identify women at risk of under- or overweight. 相似文献