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431.
Valencakova A Halanova M 《Comparative immunology, microbiology and infectious diseases》2012,35(1):1-7
The microsporidia are emerging agents of infectious disease in both immunocompromised and immunocompetent mammals. Recently, there has been an increased interest in studying the immunobiology of microsporidiosis. This paper discusses the humoral and cell-mediated immune responses to Encephalitozoon spp. The T-cell-mediated responses appear to be most important in conferring resistance. This has become evident by the lethal effects of microsporidiosis in T-cell-deficient hosts. However, much still needs to be learned about the immunobiology of microsporidiosis regarding the specific T-cell responses and the cytokines that provide protective immunity and facilitate the macrophage-mediated killing of microsporidia. Such information will become important in developing immunotherapeutic strategies to control microsporidiosis in the future. 相似文献
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436.
Jeffrey J. Richardson L. Monika Moskal Soo-Hyung Kim 《Agricultural and Forest Meteorology》2009,149(6-7):1152-1160
Leaf area index (LAI) has traditionally been difficult to estimate accurately at the landscape scale, especially in heterogeneous vegetation with a range in LAI, but remains an important parameter for many ecological models. Several different methods have recently been proposed to estimate LAI using aerial light detection and ranging (LIDAR), but few systematic approaches have been attempted to assess the performance of these methods using a large, independent dataset with a wide range of LAI in a heterogeneous, mixed forest. In this study, four modeling approaches to estimate LAI using aerial discrete-return LIDAR have been compared to 98 separate hemispherical photograph LAI estimates from a heterogeneous mixed forest with a wide range of LAI. Among the four approaches tested, the model based on the Beer–Lambert law with a single parameter (k: extinction coefficient) exhibited highest accuracy (r2 = 0.665) compared with the other models based on allometric relationships. It is shown that the theoretical k value (=0.5) assuming a spherical leaf angle distribution and the zenith angle of vertical beams (=0°) may be adequate to estimate effective LAI of vegetation using LIDAR data. This model was then applied to six 30 m × 30 m plots at differing spatial extents to investigate the relationship between plot size and model accuracy, observing that model accuracy increased with increasing spatial extent, with a maximum r2 of 0.78 at an area of 900 m2. Findings of the present study can provide useful information for selection and application of LIDAR derived LAI models at landscape or other spatial scales of ecological importance. 相似文献
437.
Nadine Konz Monika Schaub Volker Prasuhn Dominik Baenninger Christine Alewell 《植物养料与土壤学杂志》2009,172(5):615-622
Data on quantification of erosion rates in alpine grasslands remain scarce but are urgently needed to estimate soil degradation. We determined soil‐erosion rates based on 137Cs in situ measurements. The method integrates soil erosion over the last 22 y (time after the Chernobyl accident). Measured erosion rates were compared with erosion rates modeled with the Universal Soil Loss Equation (USLE). The comparison was done in order to find out if the USLE is a useful tool for erosion prediction in steep mountainous grassland systems. Three different land‐use types were investigated: hayfields, pasture with dwarf shrubs, and pasture without dwarf shrubs. Our test plots are situated in the Urseren Valley (Central Switzerland) with a mean slope steepness of 37°. Mean annual soil‐erosion rates determined with 137Cs of the investigated sites ranged between the minimum of 4.7 t ha–1 y–1 for pastures with dwarf shrubs to >30 t ha–1 y–1 at hayfields and pastures without dwarf shrubs. The determined erosion rates are 10 to 20 times higher compared to previous measurements in alpine regions. Our measurements integrated over the last 22 y, including extreme rainfall events as well as winter processes, whereas previous studies mostly reported erosion rates based on summer time and short‐term rainfall simulation experiments. These results lead to the assumption that heavy‐rainfall events as well as erosion processes during winter time and early spring do have a considerable influence on the high erosion amounts that were measured. The latter can be confirmed by photographs of damaged plots after snowmelt. Erosion rates based on the USLE are in the same order of magnitude compared to 137Cs‐based results for the land‐use type “pasture with dwarf shrubs”. However, erosion amounts on hayfields and pasture without dwarf shrubs are underestimated by the USLE compared to 137Cs‐based erosion rates. We assume that the underestimation is due to winter processes that cause soil erosion on sites without dwarf shrubs that is not considered by the USLE. Dwarf shrubs may possibly prevent from damage of soil erosion through winter processes. The USLE is not able to perform well on the affected sites. Thus, a first attempt was done to create an alpine factor for the USLE based on the measured data. 相似文献
438.
Kruczkowska Bogusława Jonczak Jerzy Gadziszewska Joanna Niska Monika Florek Wacław Degórski Marek 《Journal of Soils and Sediments》2019,19(2):848-861
Journal of Soils and Sediments - The studies aimed to reconstruct major phases of litho-morpho-pedogenic processes and past environmental changes in the Baltic coastal zone near Podd?bie... 相似文献
439.
Edwardsiella tarda was isolated from naturally infected rainbow trout (Oncorhynchus mykiss) in raceway culture on a commercial fish farm where the fish were kept at a density of 110 kg m?3 and at a water temperature of 14°C and with a photoperiod of 13 h light:11 h dark. The clinical signs of diseased fish (150 ± 20 mm standard length) were anorexia and lethargy. The most striking lesions in the fish were in the liver. There were hyperaemia and haemorrhages; on histopathological examination, the liver displayed inflammatory infiltrate in portal area, focal necrosis, dilatation of blood sinus and activation of sinusoidal cells. Infection experiments, performed 2 years after isolation of the original culture of E. tarda, were carried out under laboratory conditions at water temperatures of 15, 18 or 24°C. All experimental fish (common carp, Prussian carp, tench), intraperitoneally injected with 8 × 106 cells, demonstrated a total resistance to E. tarda. 相似文献
440.
Monika Kosmala Joanna Milala Krzysztof Kołodziejczyk Jarosław Markowski Monika Mieszczakowska Christian Ginies Catherine M. G. C. Renard 《Plant foods for human nutrition (Dordrecht, Netherlands)》2009,64(4):279-285
The polysaccharide composition of cell wall of sour cherry (Prunus cerasus var. Schattenmorelle) fruit and pomace was investigated. Furthermore, the alcohol insoluble solids composition of ‘Kelleriis’
and ‘Dobreczyn Botermo’ varieties were studied too. Yield of alcohol insoluble solids for fruits was lower than 10%, and for
pomaces circa 50%. Uronic acid was the main pectin component of alcohol insoluble solids. Enzymes used as juice processing
aids decreased the content of uronic acid. Araban and galactan side chains bonded tightly to cellulose presence was suggested by high content of arabinose and galactose in hemicellulose fraction. The process of drying at below 70 °C did not influence polysaccharide
composition of sour cherry pomaces. Alcohol insoluble solids of fruits expressed higher hydration properties than of pomaces. 相似文献