Gas sensor array for blueberry fruit disease detection and classification     

Changying Li  Gerard W. Krewer  Pingsheng Ji  Harald Scherm  Stanley J. Kays 《Postharvest Biology and Technology》2010,55(3):144-149

A conducting polymer gas sensor array (electronic nose) was evaluated for detecting and classifying three common postharvest diseases of blueberry fruit: gray mold caused by Botrytis cinerea, anthracnose caused by Colletotrichum gloeosporioides, and Alternaria rot caused by Alternaria sp. Samples of ripe rabbiteye blueberries (Vaccinium virgatum cv. Brightwell) were inoculated individually with one of the three pathogens or left non-inoculated, and volatiles emanating from the fruit were assessed using the gas sensor array 6–10 d after inoculation in two separate experiments. Principal component analysis of volatile profiles revealed four distinct groups corresponding to the four inoculation treatments. MANOVA, conducted on profiles from individual assessment days or from combined data, confirmed that the four treatments were significantly different (P < 0.0001). A hierarchical cluster analysis indicated two super-clusters, i.e., control cluster (non-inoculated fruit) vs. pathogen cluster (inoculated fruit). Within the pathogen cluster, fruit infected by B. cinerea and Alternaria sp. were more similar to each other than to fruit infected by C. gloeosporioides. A linear Bayesian classifier achieved 90% overall correct classification for data from experiment 1. Tenax? trapping of volatiles with short-path thermal desorption and quantification by gas chromatography–mass spectrometry was used to characterize volatile compounds emanated from the four groups of berries. Six compounds [styrene, 1-methyl-2-(1-methylethyl) benzene, eucalyptol, undecane, 5-methyl-2-(1-methylethyl)-2-cyclohexen-1-one, and thujopsene] were identified as contributing most in distinguishing differences in the volatiles emanating from the fruit due to infection. A canonical discriminant analysis model using the relative concentration of each of these compounds was developed and successfully classified the four categories of berries. This study underscores the potential feasibility of using a gas sensor array for blueberry postharvest quality assessment and fungal disease detection.  相似文献   

Method for determining nitrogenous heterocycle compounds in wine     

Keim H  de Revel G  Marchand S  Bertrand A 《Journal of agricultural and food chemistry》2002,50(21):5803-5807

Qualitative and quantitative analyses of N-heterocycle compounds were conducted by using a liquid-liquid extraction followed by additional chemical silica gel purification and injection into a gas chromatographic (GC) column coupled to a nitrogen-phosphorus detector (NPD). The purified extract fraction was investigated by GC-NPD and by GC-mass spectrometry. The compounds identified and quantified in wines were 2,4,5-trimethyloxazole, 2,4-dimethylthiazole, and 4-methylthiazole by GC-NPD and both 2-acetylthiazole and 2-acetyl-2-thiazoline by GC-MS. The procedure was used to analyze different wines and gave reliable and reproducible results.  相似文献   

Prognosis of Methane Formation by River Sediments (9 pp)     

Harald Köthe 《Journal of Soils and Sediments》2006,6(2):75-83

Background   Under anoxic conditions typically prevailing in disposal sites for dredged sediment, methanogenesis is the terminal step during microbial degradation of sediment organic matter. Sediment gas production may pose several problems to site management and post-closure utilisation. Depending on the magnitude of gas/methane formation and the intended utilisation of the site, countermeasures will have to be effected during and after deposition of the dredged material. For this purpose it may be of interest to pre-estimate the extent of gas formation from simple sediment variables. Therefore, the aim of the investigations presented here was to analyse the interrelations between gas formation and sediment physical, chemical and biological qualities. Methods   Freshly sampled riverbed sediment from nine German federal waterways was analysed for standard solid physical and chemical parameters, pore water composition, cell counts of methanogenic and sulfate-reducing bacteria, and gas formation over a period of 500 days. Particle size and density fractionation were carried out in order to characterise organic matter quality. Correlations between methane formation and sediment chemical, physical and microbiological characteristics were tested using linear and multiple correlation analysis. Results and Discussion   The selected sediments, including two with marine influence, differed strongly regarding texture, chemical parameters, pore water composition, and methanogen cell counts. The course of methane formation was found to follow distinct phases. The commencement of methane formation was preceded by a lag phase of variable duration. The lag phase was followed by a strong increase of the methane formation rate up to a sediment-characteristic maximum of 5–30 nmol CH4 h–1 g dw–1. Eventually, the rate of methane formation decreased and reached a more stable, long-term level. The extent and amplitude of each phase varied strongly between sediments and could be correlated well with only a few standard analytical parameters, despite the strong heterogeneity of sediment with respect to chemical, physical, and biological characteristics. Lag phase duration depended strongly on the content of inorganic electron acceptors and also on the number of methanogens present at the beginning of the experiment. Maximum and steady state methanogenesis were mainly determined by sediment total nitrogen. As analysis of sediment density fractions revealed that total nitrogen reflected the share of readily degradable macroorganic matter. Conclusion and Outlook   The results imply that the observed methane formation is a function of the temporally changing balance of the availability of electron acceptors and H2, and the share of easily degradable organic matter. For fresh riverbed sediments, the latter may be deduced from total nitrogen content. Overall, the results showed that methane formation by freshly dredged material may well be pre-estimated from standard analytical data within the first few years of deposition. However, the differently degradable organic matter pools will change over time with respect to size, chemical nature and association with the sediment mineral phase. It can thus be expected that the correlations found in this study will not be readily transferable to older materials. Further studies on the gas formation and organic matter quality by older sediments, e.g. from older dredged material disposal sites of known age, should be conducted and results should be combined with existing organic matter degradation models in order to improve the prediction of sediment gas formation over time.  相似文献   

Beiträge zur Kenntnis der als Obstpflanzen kultiviertenPassiflora-Arten     

Harald Ohle 《Genetic Resources and Crop Evolution》1975,23(1):107-129

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Regionalization of critical loads under uncertainty     

Andreas Barkman  Per Warfvinge  Harald Sverdrup 《Water, air, and soil pollution》1995,85(4):2515-2520

The steady-state model PROFILE was used to perform Monte Carlo simulations of critical loads of acidity and exceedances of forest soils for 128 sites in the province of Scania, southern Sweden. Statistical tests showed that 100 sites had normal distributed critical loads and exceedances and that the variance of these parameters was statistically equal for all sites. Pooled estimates of the standard deviation was 0.19 and 0.31 kmol_c ha^?1 yr^?1 for the critical loads and exceedances, respectively. Introduction of uncertainties, expressed as confidence intervals, in the cumulative distribution function for critical loads showed that overlaps between percentiles were substantial. The 5%-ile was systematically equal to the 57%-ile using a 67% confidence interval and equal to the 87%-ile when a 95% confidence level was chosen. The overlaps of percentiles cause a reduction of acidic deposition according to the mean value of the 5%-ile to protect only 68% of the ecosystem area with an 84% probability and not a guaranteed protection of 95% as if uncertainties did not exist. Thus, uncertainties make it possible to advocate reductions to levels of deposition below the 5%-tile of critical loads.  相似文献   

Taxonomy and evolution of cultivated plants: Literature review 1981/1982     

Dr. Jürgen Schultze-Motel  Dr. Reinhard Fritsch  Dr. Karl Hammer  Dr. Peter Hanelt  Dr. Joachim Kruse  Dr. Harald Ohle  Klaus Pistrick 《Genetic Resources and Crop Evolution》1983,31(2):299-316

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Taxonomy and evolution of cultivated plants: Literature review 1980/1981     

Dr. Jürgen Schultze-Motel  Dr. Reinhard Fritsch  Dr. Karl Hammer  Dr. Peter Hanelt  Dr. Joachim Kruse  Dr. Helga I. Maass  Dr. Harald Ohle  Klaus Pistrick 《Genetic Resources and Crop Evolution》1982,30(2):273-291

Summary Important papers on taxonomy and evolution of cultivated plants published in 1980 and 1981 were compiled and briefly discussed.

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Taxonomie und Evolution der Kulturpflanzen: Literaturübersicht 1980/1981

Zusammenfassung Wichtige Arbeiten über Taxonomie und Evolution der Kulturpflanzen aus den Jahren 1980 und 1981 wurden zusammengestellt und kurz kommentiert.

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: 1980–1981 .

, 1980 1981 . .

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Herrn Prof. Dr. Dr. h. c. mult. H.Stubbe aus Anlaß der 80. Wiederkehr seines Geburtstages gewidmet.  相似文献   

Taxonomy and evolution of cultivated plants: Literature review 1988/1989     

Jürgen Schultze-Motel  Reinhard Fritsch  Karl Hammer  Peter Hanelt  Joachim Kruse  Helga I. Maass  Harald Ohle  Klaus Pistrick 《Genetic Resources and Crop Evolution》1990,38(3):417-434

Summary Important papers on taxonomy and evolution of cultivated plants published in 1988 and 1989 were compiled and briefly discussed.

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Taxonomie und Evolution der Kulturpflanzen: Literaturübersicht 1988/1989

Zusammenfassung Wichtige Arbeiten über Taxonomie und Evolution der Kulturpflanzen aus den Jahren 1988 und 1989 wurden zusammengestellt und kurz kommentiert.

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: 1988–1989

, 1988 1989 . .

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Climate change and nature conservation in Central European forests: A review of consequences, concepts and challenges     

Mirjam Milad  Harald SchaichMatthias Bürgi  Werner Konold 《Forest Ecology and Management》2011,261(4):829-843

With a predicted rise in average global surface temperature at an unprecedented rate, as well as changes in precipitation and disturbance regimes, climate change will bring forth new challenges for nature conservation in forest ecosystems. Species and habitats to be protected will be affected as well as related concepts and area specific objectives. Climate change impacts are likely to be aggravated by other anthropogenic stresses such as fragmentation, deposition or habitat destruction. To be reliable and effective, current objectives and guidelines of forest conservation need to be reassessed and improved. Our study analyses possible impacts of climate change on forests and identifies key future challenges for nature conservation in forests and ecosystem research. We reviewed 130 papers on climate change impacts on forest ecosystems and species published between 1995 and 2010. The geographical focus of the study is Central Europe. Papers were analysed accounting for direct and indirect impacts of gradual changes as well as stochastic disturbance events in forest ecosystems and their possible consequences for nature conservation.Even though broader aspects of nature conservation (protected areas, biodiversity) are frequently mentioned, little attention is given to forest-specific nature conservation. Particular aspects are insufficiently represented, such as the influence of climate change on different forest succession stages, the development of dead wood volume and quality, responses of secondary broadleaved species, azonal or extrazonal forests as well as ancient woodlands or remnants of historical silvicultural systems. Challenges arise in the context of great uncertainties about future developments. Nature conservation concepts and objectives in forests need to be adapted either within a permanent evaluation process or through the inclusion of further changes a priori, even if they are to some extent unpredictable. In some cases adaptation measures within nature conservation (e.g. adjusting protected areas) may conflict with interests of other stakeholders. Further research, particularly on interrelations between different impacts and the adaptive capacity of current forest ecosystems, associated species and existing genotypes is urgently needed. The scale and complexity of the task at hand calls for the establishment and further strengthening of international research networks.  相似文献   

Weather and human impacts on forest fires: 100 years of fire history in two climatic regions of Switzerland     

Thomas Zumbrunnen  Gianni B. PezzattiPatricia Menéndez  Harald BugmannMatthias Bürgi  Marco Conedera 《Forest Ecology and Management》2011,261(12):2188-2199

Understanding the factors driving past fire regimes is crucial in the context of global change as a basis for predicting future changes. In this study, we aimed to identify the impact of climate and human activities on fire occurrence in the most fire-prone regions of Switzerland. We considered forest fires, land use and meteorological data over the period 1904-2008 in the neighboring mountain cantons (states) of Valais and Ticino, which are characterized by distinct climatic regimes.The presence/absence of fire ignitions was analyzed using the Nesterov ignition index (as a proxy for fire weather), road density (for ignition sources), livestock density (for biomass removal), and change in forest area (for fire-prone abandoned agricultural areas).We found that fire weather played a key role in fire occurrence in both regions. Road and livestock densities had similar influences in the two cantons. However, while the increase in forest area was well correlated with fire occurrence in Ticino, no such correlation was evident in Valais, probably because land abandonment and forest cover change have been less extensive there. Our findings emphasize the non-linear nature of the relationships between fire occurrence and anthropogenic drivers, as we found thresholds above which road density was no longer correlated with fire occurrence. This implies that the projected future increase and spatial concentration of the human population may not result in a further increase in fire risk in intermediately to densely populated areas in both cantons.The driving factors behind fire activity differ slightly in the two cantons, in particular with increasing forest area enhancing fire occurrence in Ticino but not in Valais. These differences should be taken into account when assessing future fire risk, especially in Valais where the potential for an increase in the fire-prone area is still high. Fires are likely to become more frequent in a warmer climate, but future fire activity may develop differently in the two cantons. This should be taken into account when planning optimized fire prevention measures. This case study should help to better understand fire activity in highly populated regions where fire activity is still moderate but might markedly increase under a projected more fire-prone climate.  相似文献