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381.
OBJECTIVE: To describe the case of Congo as an example of the assessment and appropriateness of donor operational and sectoral strategies in a complex emergency. DESIGN AND SETTING: The paper reports the findings of an external evaluation of operations financed by the European Commission Humanitarian Office in the Democratic Republic of Congo (DRC). RESULTS: The Congolese health system is suffering from severe deterioration. What is functioning in the public health context is donor-dependent with high costs and limited coverage. Despite a relatively favourable agro-climatic situation, food shortage and famine severely affect the nutritional status of large population groups. In this context, humanitarian programmes have generally improved access to health care and the nutritional status of beneficiaries. The reduction of malnutrition in project areas is often demonstrated even though the context did not permit consolidation of these results. Malnutrition continues to claim a massive cost of lives owing to the effect of widespread food insecurity that follows a circular cause-and-effect pattern of very low food production and extreme poverty. CONCLUSIONS: The current context in DRC does not correspond yet to 'post-crisis': neither at population level with regard to indicators of poverty, malnutrition, disease and death, nor at institutional level, with regard to state support to institutions. In these situations, the international community is often called upon to replace the state as service provider. Integrated humanitarian actions should be the future of relief projects in DRC. Health, nutrition and food security components should be considered a standard public health intervention strategy representing the most sensible approach to address the needs of the affected population.  相似文献   
382.
Grapefruit seed extracts are used in cosmetics, food supplements, and pesticides because of their antimicrobial properties, but suspicions about the true nature of the active compounds arose when synthetic disinfectants such as benzethonium or benzalkonium chloride were found in commercial products. The HPLC method presented herein allows the quality assessment (qualitative and quantitative) of these products for the first time. On the basis of a standard mixture of 18 preservatives most relevant for food and grapefruit products, a method was developed allowing the baseline separation of all compounds within 40 min. Optimum results were obtained with a C-8 stationary phase and a solvent system comprising aqueous trifluoroacetic acid, acetonitrile, and 2-propanol. The assay was fully validated and shown to be sensitive (LOD < or= 12.1 ng on-column), accurate (recovery rates > or = 96.1%), repeatable (sigma(rel) < or = 3.5%), precise (intra-day variation < or = 4.5%, interday variation < or = 4.1%), and rugged. Without any modifications the method could be adopted for LC-MS experiments, where the compounds of interest were directly assignable in positive ESI mode. The quantitative results of several products for ecofarming confirmed previous studies, as seven out of nine specimens were adulterated with preservatives in varying composition. The samples either contained benzethonium chloride (2.5-176.9 mg/mL) or benzalkonium chloride (138.2-236.3 mg/mL), together with smaller amounts of 4-hydroxybenzoic acid esters, benzoic acid, and salicylic acid.  相似文献   
383.
Garlic and shallot are important vegetable and spice plants, garlic is also a medicinal crop widely used throughout the world. Both belong to the genus Allium, which has been a main target of the taxonomical research at the IPK for many years. Therefore, the IPK’s living collection of Allium is one of the world’s largest special collections of this genus with garlic and shallot being essential parts of this collection. Furthermore, they are subject to special activities to preserve the material in vitro and in cryopreservation. Both methods help protecting valuable germplasm from abiotic and biotic threats and reduce the maintenance costs in the long term. At present, the garlic collection maintained at the IPK incorporates germplasm of 509 accessions in total including all safety duplicates not offered for exchange. Of shallot, 114 accessions are present as well. Passport data as well as phenotypic data of 159 accessions of garlic, one of great headed garlic and 16 of shallot are included in the Garlic and Shallot Core Collection Database (GSCC). An additional part of the database is a comprehensive collection of images illustrating morphological characteristics of the accessions. Exploration of the information is supported by a web-based application. The GSCC is available at http://www.ipk-gatersleben.de/databases/gscc.  相似文献   
384.
Soil respiration represents the second largest CO2 flux of the terrestrial biosphere and amounts 10 times higher than the current rate of fossil‐fuel combustion. Thus, even a small change in soil respiration could significantly intensify—or mitigate—current atmospheric increases of CO2, with potential feedbacks to climate change. Consequently, to understand future dynamics of the earth system, it is mandatory to precisely understand the response of soil respiration to changing environmental factors. Among those changing factors, temperature is the one with clearest and most certain future trend. The relationship of soil respiration to environmental factors and particular temperature has been tackled at a variety of scales—from laboratory via field to global scale, with each of the approaches having its particular problems, where results from different scales are sometimes contradictory. Here, we give an overview of modeling approaches to soil respiration, discuss the dependencies of soil respiration on various environmental factors, and summarize the most important pitfalls to consider when analyzing soil respiration at the respective scale. We then introduce a model–data synthesis framework that should be able to reconcile and finally integrate apparently contradictory results from the various scales.  相似文献   
385.
The relationship and mechanisms among weathering processes, cation fluxes, clay mineralogy, organic matter composition and stability were studied in soils developing on basaltic material in southern Italy (Sicily). The soils were transitions between Phaeozems and Vertisols. Intense losses of the elements Na, Ca and Mg were measured indicating that weathering has occurred over a long period of time. The main weathering processes followed the sequence: amphibole, mica, volcanic glass or if ash was the primary source → smectite → interstratified smectite–kaolinite → kaolinite. Kaolinite formation was strongly related to high Al, Mg and Na losses. The good correlation between oxyhydroxides and kaolinite in the soils suggests that (macro)aggregates have formed due to physical or electrostatic interactions between the 1:1 clay minerals and oxides. The stability of organic matter was investigated with a H2O2-treatment that assumes that chemical oxidation mimics the natural oxidative processes. The ratio of C after the H2O2 treatment to the total organic C ranged from 1–28%. No correlation between clay content and organic matter (labile or stable fraction) was found. The refractory organic fraction was enriched in aliphatic compounds and did not greatly interact with the kaolinite, smectite or poorly crystalline Fe or Al phases. A part of this fraction (most probably proteins) was bound to crystalline Fe-oxides. In contrast, the oxidisable fraction showed a strong relationship with poorly crystalline oxyhydroxides and kaolinite. Surprisingly, smectite did not contribute to the stabilisation of any of the organic C fractions. The stabilisation of organic matter in the soils has, therefore, two main mechanisms: 1) the protection of labile (oxidisable with H2O2) organic matter, including also aromatic-rich compounds such as charcoal, by the formation of aggregates with oxyhydroxides and kaolinite and 2) the formation of a refractory fraction enriched in aliphatic compounds.  相似文献   
386.
A rapid technique for the isolation of polymeric polyphenols from red wine has been developed and validated. A copolymer reversed-phase SPE cartridge was utilized in conjunction with predominantly organic eluents to provide three phenolic fractions from red wine without the need for sample pretreatment. The first fraction contained the bulk of the monomeric and oligomeric phenolic material, while the second and third fractions contained the polymeric polyphenolic compounds, as determined by HPLC analysis. The two polymeric polyphenolic fractions differed in their solubility and extent of pigmentation, and the differences appeared to be related to wine age. This method contrasted with other available fractionation techniques because the interfering, nonpolymeric material can be removed in a single wash fraction, while the polymeric material is separated into two distinct fractions based on their diverse physicochemical properties. It is anticipated that the rapid access to discrete polymeric fractions afforded by this method will be of benefit in furthering the understanding of red wine polymeric polyphenols.  相似文献   
387.
Background, aim, and scope  The groundwaters of Western Siberia contain high concentrations of iron, manganese, silicon, ammonium, and, in several cases, hydrogen sulfide, carbonic acids, and dissolved organic substances. Generally, the groundwaters of Western Siberia can be divided into two major types: one type with a relatively low concentration of humic substances and high hardness (water of A type) and a second type with a relatively low hardness and high concentration of humic substances (water of B type). For drinking water production, the waters of A type are mostly treated in the classical way by aeration followed by sand bed filtration. The waters of B type often show problems when treated for iron removal. A part of iron practically does not form the flocs or particles suitable for filtration or sedimentation. The aim of this work was to determine the oxidizability of Fe(II), to characterize the iron colloids, and to investigate the complexation of the iron ions with humic substances and the coagulation of the iron colloids in the presence of dissolved organic matter. Materials and methods  Water samples of the A and B types were taken from bore holes in Western Siberia (A type: in Tomsk and Tomsk region, B type: in Beliy Yar and Kargasok). Depth of sampling was about 200 m below surface. The oxidation of the groundwater samples by air oxygen and ozone was done in a bubble reactor consisting of a glass cylinder with a gas-inlet tube. To produce ozone, a compact ozone generator developed by Tomsk Polytechnic University was used. For the characterization of the colloids in the water of B type, the particle size distribution and the zeta potential were measured. To investigate the formation of complexes between iron and humic substances in the water of B type, size exclusion chromatography was used. The coagulation behavior of iron in the presence of dissolved organic substances was investigated at different pH values. The agglomerates were detected by measuring the optical density using a UV-Vis spectrometer. Results  Ozone showed, as expected, a faster oxidation of Fe(II) than air oxygen. The rate constants for Fe(II) oxidation were not much different for the waters of A and B types when the same oxidation process was used. However, the removal of iron after oxidation and filtration was higher in the water of A type than in the water of B type. No evidence for the formation of soluble complexes between iron and humic substances were found. In the water of A type, the coagulation process started at pH = 4.5 and accelerated with increasing pH value. In the water of B type, the coagulation of colloids occurred only at pH = 11 and higher. Discussion  The oxidation experiments indicated no major effect of dissolved organic carbon concentration on the kinetics of Fe(II) oxidation. In contrast to this, the humic substances showed a significant influence on the aggregation behavior of the iron hydroxide colloids. Due to the sorption of humic substances on the iron hydroxide colloids, they were highly stable in the pH range between 4.5 and 10. The particle size measurements confirmed the presence of small colloids in the water of B type. In contrast to this, the iron hydroxide colloids aggregated rapidly at pH = 11. Conclusions  The results showed a great influence of humic substances on the iron removal from groundwaters of Western Siberia with high organic content. The sorption of humic substances on the iron colloids does not obviously allow their coagulation and formation of flocs suitable for filtration or sedimentation. Recommendations and perspectives  By treatment of groundwaters containing high amounts of humic substances, some problems with the removal of iron are likely to occur. To increase the effectiveness of iron removal, the surface coating and pH-dependent charge effects should be taken into account by the selection and optimization of water treatment processes. The iron colloids coated by humic substances should be separated from the water phase by membrane filtration or by flocculation followed by filtration through different solid materials.  相似文献   
388.
Endemic species are not a uniform group in terms of range size, habitat preferences, and ecological plasticity. Based on a recent inventory of endemic vascular plant species in Austria, we analysed distribution patterns, altitudinal distribution and habitat preferences of endemic species and analysed the correlation of range size and niche breadth. The inventory includes 103 vascular plant taxa (species and subspecies) endemic to Austria.Grid cells (cell size ca. 35 km2) with highest taxon numbers (max. 25 taxa) are limited to the Northeastern Calcareous Alps, whereas highest numbers of acidophilous endemics occur in the easternmost high-mountain chains of the Central Alps. The majority of endemics (61 taxa; 59.2%) are found on calcareous bedrock, 6 taxa (5.8%) on intermediate substrates, and 29 (28.2%) on siliceous bedrock. The range size of endemic vascular plant taxa is strongly skewed towards very narrow distributions – 45 taxa are restricted to <20 grid cells. Average range sizes differ markedly between endemics of different broad habitat types, endemics of habitats with limited and patchy distribution (serpentine vegetation, dry grassland) having the smallest ranges.The altitudinal distribution of endemic plant taxa peaks at high altitudes, in the subalpine and lower alpine altitude belt. Below the tree line, endemics predominantly colonize extra- and azonal dry or wet habitats, whereas above the tree line, zonal alpine grassland and azonal vegetation types (scree, rocks, snowbeds) are equally essential to the endemic flora. Niche breadth of endemics is positively, however moderately, correlated with range size. This correlation is stronger for the altitudinal distribution than for the number of habitats colonized.The distribution patterns and ecology of endemics differ considerably from overall biodiversity patterns and must be addressed appropriately in conservation strategies. Small niche-breadths and the specific habitat requirements of endemics of very localized distribution render these taxa highly vulnerable to climate change.  相似文献   
389.
Overgrazing has led to severe degradation and desertification of semi-arid grasslands in Northern China over the last decades. Despite the fact that vegetation is often heterogeneously distributed in semi-arid steppes, little attention has been drawn to the effect of grazing on the spatial distribution of soil properties. We determined the spatial pattern of soil organic carbon (SOC), total nitrogen (Ntot), total sulphur (Stot), bulk density (BD), pH, Ah thickness, and carbon isotope ratios (δ13C) at two continuously grazed (CG) and two ungrazed (UG79 = fenced and excluded from grazing in 1979) sites in Leymus chinensis and Stipa grandis dominated steppe ecosystems in Inner Mongolia, Northern China. Topsoils (0–4 cm) were sampled at each site using a large grid (120 m × 150 m) with 100 sampling points and a small plot (2 m × 2 m) with 40 points. Geostatistics were applied to elucidate the spatial distribution both at field (120 m × 150 m grid) and plant (2 m × 2 m plot) scale. Concentrations and stocks of SOC, Ntot, Stot were significantly lower and BD significantly higher at both CG sites. At the field scale, semivariograms of these parameters showed a heterogeneous distribution at UG79 sites and a more homogeneous distribution at CG sites, whereas nugget to sill ratios indicated a high small-scale variability. At the plant scale, semivariances of all investigated parameters were one order of magnitude higher at UG79 sites than at CG sites. The heterogeneous pattern of topsoil properties at UG79 sites can be attributed to a mosaic of vegetation patches separated by bare soil. Ranges of autocorrelation were almost congruent with spatial expansions of grass tussocks and shrubs at both steppe types. At CG sites, consumption of biomass by sheep and hoof action removed vegetation patches and led to a homogenization of chemical and physical soil properties. We propose that the spatial distribution of topsoil properties at the plant scale (<2 m) could be used as an indicator for degradation in semi-arid grasslands. Our results further show that the maintenance of heterogeneous vegetation and associated topsoil structures is essential for the accumulation of SOM in semi-arid grassland ecosystems.  相似文献   
390.
The Black Forest is considered to be a rather unfavorable area, having a short vegetation period, low mean annual temperatures, high precipitation, and a pronounced relief. These conditions do not favor agricultural land use and thus it is widely accepted that people only began using the land intensively during the Middle Ages. In this integrated study 17 soil profiles, two peat bogs and a database of archaeological finds were used to reconstruct past land use impacts on the environment. AMS–14C datings of charcoals, luminescence datings of colluvial deposits, archaeological finds and pollen records indicate land use already during the Neolithic. This pre‐medieval land use might be related to seasonal settlements dominated by pastoralism and the use of wood or bedrock to build settlements and infrastructure or as energy supply. There is new evidence of human activity dating back to the Bronze and Iron Age, which is a discrepancy to the absence of archaeological finds in the direct vicinity of the studied sites. With the beginning of the Middle Ages land use practices changed, most likely with the expansion and intensification of agricultural land use, which coincides with the increasing use of natural resources in the Black Forest. Hence, the main phases of colluvial deposition date to the Middle Ages and Modern Times. Increased contents of As, Cr, Cu, Pb, or Zn in medieval colluvial deposits might indicate smelting or mining, even though there are no known archeological sites pointing to such activities nearby. Whereas the pattern of colluvial deposition in the southeastern Black Forest points to distinct, but local land use in pre‐medieval times and to intensified and widespread land use since the Middle Ages, thick and multi‐layered colluvial deposits indicate intensive land use in the neighboring Baar region since the Neolithic. The different land use patterns of these two regions originate from the rather favorable conditions for agriculture in terms of soils, climate, and topography in the Baar region compared to the unfavorable conditions in the Black Forest.  相似文献   
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