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991.
Synoptic meteorological conditions for precipitating systems over South Korea are characterized into several similar types using a clustering technique based on the K-mean principles with the daily mean 850 hPa grid pointed geopotential height in the spatial resolution of 5° × 5° data obtained from NCEP in the domain of 25° ~ 50°N and 110° ~ 140°E for five years from 1994 to 1998. The consecutive three-day gridded NCEP data with the precipitation event on the last day over South Korea are used for the cluster analysis. With the use of the precipitation chemistry monitored data at 8 sites in South Korea, wet depositions of SO4 2?, NO3 ? and NH4 + belonging to each cluster are examined to identify the deposition levels for each cluster. The result indicates that the present methodology is found to identify the deposition levels clearly and be used more practically in the field of acid rain study without heavy computational requirement. 相似文献
992.
Jan Baier Vera Baierová Z. Bartošová D. Ledvinková 《Archives of Agronomy and Soil Science》2013,59(3-4):313-337
The set of twenty long‐term field nutrition trials starting from 1957 at five sites. The sites differed by their altitude (from 180 m to 620 m) with average daily temperatures (from 6,8°C m to 9°C m) and soil type (from chernozem to brown podsolic soil) Provided mainly the following results: ? The geonomic division to the fertile sugarbeet region and less fertile potato region did not strictly differentiate the influence of fertilizer and climatic effects to the crop yields. ? The effect of fertilizing was dependent on the nutrient content and on the conditions of releasing and binding of the nutrients in soil. ? The precipitation regime has a strong influence on the effect of the nitrogen escalated doses. ? The facts concerning the nutrient intake are very precious knowledge. These facts have not been examined yet during the long‐term trials. ? The site effect, particularly its climatic conditions, on the nutrient intake is often more obvious compared to the fertilizing effect. ? Very interesting impulses for further research monitoring during the long‐term trials was contributed by “mapping”; of soil capacity to provide nutrients to plants at various sites and under different climate. 相似文献
993.
Masahiro Natsume Asaho Nagagata Marja Aittamaa Naoko Okaniwa Panu Somervuo Hans-Peter Fiedler Jan F. Kreuze Veli-Matti Rokka Hans Bång Hiroshi Kawaide Jari P. T. Valkonen 《Journal of General Plant Pathology》2018,84(2):108-117
Streptomyces spp. are a highly diverse group of bacteria most of which are soil-inhabiting saprophytes. A few are plant pathogens that produce a family of phytotoxins called thaxtomins and cause significant economic losses, e.g., by reducing the marketability of potato tubers (Solanum tuberosum). In northern Europe, S. scabies, S. turgidiscabies and S. europaeiscabiei are the most common plant pathogenic species. In this study, a Streptomyces strain isolated from a netted scab lesion on a tuber of potato cv. Bintje in northern Sweden was identified as S. turgidiscabies but was found to differ in the genomic region carrying genes required for thaxtomin biosynthesis. Our results showed that the strain did not produce thaxtomin but rather phytotoxin fridamycin E, which is an anthraquinone novel to plant pathogenic Streptomyces spp. Fridamycin E was shown to reduce or inhibit sprouting of potato microtubers in vitro. While fridamycin E is known to have antibiotic activity against Gram-positive bacteria, the inhibitory activity of fridamycin E on plant growth is a novel finding. 相似文献
994.
Regional Sediment Deficits in the Dutch Lowlands: Implications for Long-Term Land-Use Options (8 pp)
Michiel J. van der Meulen Ad J. F. van der Spek Ger de Lange Stephan H. L. L. Gruijters Serge F. van Gessel Buu-Long Nguyen Denise Maljers Jeroen Schokker Jan P. M. Mulder Rob A. A. van der Krogt 《Journal of Soils and Sediments》2007,7(1):9-16
Background, Aim and Scope
Coastal and river plains are the surfaces of depositional systems, to which sediment input is a parameter of key-importance.
Their habitation and economic development usually requires protection with dikes, quays, etc., which are effective in retaining
floods but have the side effect of retarding sedimentation in their hinterlands. The flood-protected Dutch lowlands (so-called
dike-ring areas) have been sediment-starved for up to about a millennium. In addition to this, peat decomposition and soil
compaction, brought about by land drainage, have caused significant land subsidence. Sediment deficiency, defined as the combined
effect of sediment-starvation and drainage-induced volume losses, has already been substantial in this area, and it is expected
to become urgent in view of the forecasted effects of climate change (sea-level rise, intensified precipitation and run-off).
We therefore explore this deficiency, compare it with natural (Holocene) and current human sediment inputs, and discuss it
in terms of long-term land-use options.
Materials and Methods:
We use available 3D geological models to define natural sediment inputs to our study area. Recent progress in large-scale
modelling of peat oxidation and compaction enables us to address volume loss associated with these processes. Human sediment
inputs are based on published minerals statistics. All results are given as first-order approximations.
Results:
The current sediment deficit in the diked lowlands of the Netherlands is estimated at 136 ± 67 million m3/a. About 85% of
this volume is the hypothetical amount of sediment required to keep up with sea-level rise, and 15% is the effect of land
drainage (peat decomposition and compaction). The average Holocene sediment input to our study area (based on a total of 145
km3) is ~14 million m3/a, and the maximum (millennium-averaged) input ~26 million m3/a. Historical sediment deficiency has
resulted in an unused sediment accommodation space of about 13.3 km3. Net human input of sediment material currently amounts
to ~23 million m3/a.
Discussion:
As sedimentary processes in the Dutch lowlands have been retarded, the depositional system's natural resilience to sea-level
rise is low, and all that is left to cope is human countermeasure. Preserving some sort of status quo with water management
solutions may reach its limits in the foreseeable future. The most viable long-term solutions therefore seem a combination
of allowing for more water in open country (anything from flood-buffer zones to open water) and raising lands that are to
be built up (enabling their lasting protection). As to the latter, doubling or tripling the use of filling sand in a planned
and sustained effort may resolve up to one half of the Dutch sediment deficiency problems in about a century.
Conclusions:
Conclusions, Recommendations and Perspectives. We conclude that sediment deficiency – past, present and future – challenges
the sustainable habitation of the Dutch lowlands. In order to explore possible solutions, we recommend the development of
long-term scenarios for the changing lowland physiography, that include the effects of Global Change, compensation measures,
costs and benefits, and the implications for long-term land-use options.
Recommendations and Perspectives:
- 相似文献
995.
In its simplest case, ANOVA can be seen as a generalization of the t-test for comparing the means of a continuous variable in more than two groups defined by the levels of a discrete covariate, a so-called factor. Testing is then typically done by using the standard F-test. Here, we consider the special but frequent case of factor levels that are ordered. We propose an alternative test using mixed models methodology. The new test often outperforms the standard F-test when factor levels are ordered. We illustrate the proposed testing procedure in simulation studies and three typical applications: nonparametric dose response analysis in agriculture, associations between rating scales and a continuous outcome, and testing differentially expressed genes with ordinal phenotypes. 相似文献
996.
Kristof Brijs Jeroen A. Ingelbrecht Christophe M. Courtin Linda Schlichting Brian A. Marchylo Jan A. Delcour 《Cereal Chemistry》2004,81(3):361-368
The combined effects on pasta properties of 1) varying dosages of endoxylanases (EC 3.2.1.8) from Aspergillus aculeatus and Bacillus subtilis and 2) lower levels of water during pasta dough processing were studied. The A. aculeatus endoxylanase has high selectivity toward water‐extractable arabinoxylan (WE‐AX), whereas B. subtilis endoxylanase preferentially hydrolyzes water‐unextractable arabinoxylan (WU‐AX). Pasta was produced on a microscale (50.0 g) from the semolinas of both a strong (AC Navigator) and a moderately strong (AC Avonlea) durum wheat cultivar. The levels of added water in endoxylanase‐treated pastas were adjusted to obtain the same maximal farinograph consistencies as for the control pastas. The extruded pastas were dried with drying cycles at 40, 70, or 90°C. Apart from increasing levels of solubilized arabinoxylans, these treatments had little effect on the color, optimal cooking time, and firmness of the resulting pasta. High enzyme concentrations and low (40°C) drying temperature resulted in clearly or much less checked final products for the B. subtilis and A. aculeatus enzyme, respectively. Upon cooking, the enzymically formed low molecular weight arabinoxylans were retained better in the pasta strands than their equally low molecular weight arabinogalactan counterparts. 相似文献
997.
Red mold dioscorea has greater hypolipidemic and antiatherosclerotic effect than traditional red mold rice and unfermented dioscorea in hamsters 总被引:1,自引:0,他引:1
Monascus-fermented red mold dioscorea (RMD) was proven to produce higher monacolin K levels than red mold rice (RMR) in our previous study. The goal of this study is to investigate whether the novel RMD had more hypolipidemic and antiatherosclerotic effect than traditional red mold rice. The daily dose of RMR for adults was recommended as 1 g, which corresponded to 96 mg/kg/day for hamsters. Therefore, high cholesterol diet-induced hyperlipidemic hamsters were daily administrated with a 0.5-fold (48 mg/kg/day), a 1-fold (96 mg/kg/day), or a 5-fold dose (480 mg/kg/day) of RMD for 8 weeks. Furthermore, a 1-fold dose of RMR (96 mg/kg/day) and unfermented dioscorea (96 mg/kg/day) were also respectively used to evaluate the effect of hypolipidemic and antiarteriosclerosis. The results indicated that only needing a 0.5-fold dose of RMD was able to significantly lower total cholesterol (by 13.78%, p<0.001), triglyceride (by 38.74%, p<0.01), and low-density lipoprotein cholesterol levels (by 43.11%, p<0.05) as well as maintain a high-density lipoprotein cholesterol level, as compared to the hyperlipidemic group. RMD including a higher monacolin K level and a dioscorea substrate was able to exhibit a more significant difference in the hypolipidemic effect than RMR or unfermented dioscorea. Both RMR and dioscorea exhibited potent in vitro antioxidative ability and in vivo protection against hypolipidemia-induced oxidative stress. Therefore, the antioxidative ability of RMD provided by Monascus metabolites (dimerumic acid, tannin, phenol, etc.) as well as dioscorea was able to perform more antiatherosclerotic effects on increasing total antioxidant status, catalase, and superoxide dismutase activity and repressing lipid peroxidation and atherosclerotic plaque than RMR and dioscorea. 相似文献
998.
Yvonne I. Verkuil Natalia Karlionova Eldar N. Rakhimberdiev Joop Jukema Jan J. Wijmenga Jos C.E.W. Hooijmeijer Pavel Pinchuk Eddy Wymenga Allan J. Baker Theunis Piersma 《Biological conservation》2012,149(1):51-59
The fuelling performance of long-distance migrants at staging areas indicates local conditions and determines the viability of migration routes. Here we present a first case study where long-term fuelling performance was documented along two migration routes with differential population trends. Ruffs (Philomachus pugnax) are shorebirds of inland freshwater wetlands that migrate from the sub-Saharan wintering grounds, via Europe, to the northern Eurasian breeding grounds. Assessments from 2001 to 2008 of fuelling during northward migration at the major western and eastern staging site revealed that daily mass gain rates steeply declined across years in the grasslands for dairy production in Friesland, The Netherlands, and remained constant in the Pripyat floodplains in Belarus, 1500 km further east. Migrants in Friesland decreased from 2001 to 2010 by 66%, amounting to a loss of 21,000 individuals when counts were adjusted for length of stay as determined by resightings. In the same period numbers in Pripyat increased by 12,000. Ruffs individually ringed in Friesland were resighted in subsequent springs at increasingly eastern sites including Pripyat. Our results corroborate published evidence for an eastward redistribution of Arctic breeding ruffs and suggest that the decreasing fuelling rates in the westernmost staging area contribute to this redistribution. The shift implies that responses occur within a single generation. The hypothesis that the choice of route during northward migration may be driven by food availability can now be tested by creating greater areas of wet grasslands in Friesland. When local staging conditions improve we predict that ruffs will make the reverse shift. 相似文献
999.
Hur J Choi YY Park JH Jeon BW Lee HS Kim AR Lee JH 《Canadian journal of veterinary research》2011,75(1):49-56
Salmonella enterica subsp. enterica serovar Typhimurium was isolated from diarrheic piglets in 2 periods, 2000-2001 (n = 25) and 2005-2006 (n = 17). To compare the characteristics of the isolates collected during the 2 periods, all isolates were tested for antimicrobial resistance, the presence of virulence genes, and pulsed-field gel electrophoresis (PFGE) patterns. All 42 isolates were resistant to at least 1 of the 20 antimicrobials tested, and 39 (93%) were resistant to 2 or more antimicrobials. One isolate was resistant to 12 antimicrobials. Profiles of antimicrobial resistance revealed 20 resistance types. Several isolates were also resistant to quinolones and expanded-spectrum cephalosporins. Ten isolates (24%) were resistant to ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline (ACSSuT); only one isolate had been isolated in 2000-2001, indicating that this type of resistance has rapidly disseminated. Polymerase chain reaction (PCR) assays revealed that all the isolates carried invA. Among the 25 strains isolated in 2000-2001, all carried the sipA, sopA, sopD, sopE2, and ssaR genes, and 96% carried sopB and sifA. Among the 17 strains isolated in 2005-2006, all carried sifA, and approximately 90% carried sipA, sopA, sopB, sopD, sopE2, and ssaR. However, only 6 (14%) of the 42 isolates carried spvC. By PFGE analysis, all 42 strains were classified into 4 major clusters, basically by collection period. The genetic similarity according to PFGE suggests that the strains isolated from diarrheic piglets of this region within the same period may be closely related. 相似文献
1000.
The growth of small ( approximately 10-micrometer) diamond particles (on 0.1-or 0.25-micrometer seed crystals) using an effusive glow discharge nozzle for H.and a separate supersonic pyrolysis jet for .CH(3) is reported. Laser micro-Raman, scanning electron microscopy, and x-ray photoelectron spectroscopy data are presented as evidence that well-crystallized diamond is indeed formed. Resonant multiphoton ionization spectroscopy is used as a diagnostic for the gas-phase chemistry indicating that the radical sources are clean and quantitative and that there is no detectable interconversion of .CH(3) to C(2)H(2) under the conditions of the experiment. Diamond growth is found at substrate temperatures greater than or equal to 650 degrees C with no marked increase in the rate of growth up to 850 degrees C. Acetylene does not give good quality diamond under similar conditions. 相似文献