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131.
Habitat Degradation of Rhinopithecus bieti in Yunnan, China 总被引:3,自引:0,他引:3
Wen Xiao Wei Ding Liang-Wei Cui Ru-Liang Zhou Qi-Kun Zhao 《International journal of primatology》2003,24(2):389-398
Black-and-white snub-nosed monkeys (Rhinopithecus bieti) are endemic to the Trans-Himalayas in Northwest Yunnan and Southeast Tibet between the upper Yangtze and Mekong Rivers. Based on field surveys and previous reports, we identified the dark-coniferous forest, the mixed coniferous and broadleaf forest, and oak patches as suitable habitats (SH) for the monkeys. Summer grazing lands (SGL), which were made by local people cutting and burning the dark-coniferous forest at the high altitude belt, replaced SH. To have a general view of the status of the SH in Yunnan, we estimated the areas of SH and SGL from satellite images in 1997, and compared with areas estimated from aerial photo-based maps (ca. 1958). The work resulted in: 1) the area of SH was 4,169 km2 in 1997; 2) SGL was 1,923 km2; 3) during the past 40 years, the area of SH decreased by 31% (1,887 km2), and SGL increased by 204% (1,291 km2); and 4) the mean size of forest patches decreased from 15.6 to 5.4 km2. In addition, the area of SGL is positively correlated to local human population (R2 0.53), implying that the reduction and fragmentation of habitat for Rhinopithecus bieti is a result of population growth of humans, who mostly employ traditional modes of production. Only 11 monkey groups remained in the changing habitat. Considering that forests at lower elevation were also encroached upon by farmlands in a similar way, the forest ecosystem is highly threatened. The destruction will continue unless there is a change in the mode of production in the region. 相似文献
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133.
AIMS: To improve bead ingestion counts in Tetrahymena pyriformis by automated image analysis as an alternative to direct-counts. METHODS AND RESULTS: Fluorescent latex beads were added to T. pyriformis cultures for ingestion tests. The number of beads ingested by 25 cells was counted directly by epifluorescence microscopy and compared with similar data from image analysis. anova indicated that counts were not significantly different (P < 0.05). The image analysis particularly provided advantages in terms of speed. CONCLUSIONS: The image analysis is superior to direct beads counting in T. pyriformis particularly in terms of speed of analysis. SIGNIFICANCE AND IMPACT OF THE STUDY: The image analysis method is very rapid and will allow many more toxicological analyses to be undertaken with less operator error. 相似文献
134.
Kazukiyo Yamamoto 《Ecological Research》2000,15(2):203-208
A new, convenient method to estimate canopy-gap size using a camera is proposed. Canopy-gap size was estimated from two images taken with a vertically mounted, digital camera at high and low points (Ph and Pl) beneath a canopy gap. The actual (AOBS) and estimated (A1.0) canopy-gap sizes were highly correlated (R2 > 0.93) for 16 canopy gaps in the Cryptomeria japonica D. Don. plantations, and the relationship between A1.0 and AOBS was expressed as A1.0 = 1.16AOBS. Thus, the method overestimated actual canopy-gap size by an average of 16%. 相似文献
135.
A case of chronic cerebral paragonimiasis westermani 总被引:1,自引:0,他引:1
We report a chronic cerebral paragonimiasis from a 41-year-old Korean man who complains a headache and weakness of left motor neuron components. Magnetic resonance images of the brain revealed conglomerates of multiple ring-like enhancements in temporo-occipital and frontal lobes of the right hemisphere. An intradermal test for paragonimiasis westermani was positive. The patient was born near an endemic area of paragonimiasis and used to eat boiled or grilled freshwater crayfish in his childhood. Nodules in the brain were resected through craniotomies. The eggs of P. westermani were identified pathologically and parasitologically in the calcified necrotic lesions. Examinations on sputum and fecal specimens for the eggs of P. westermani were shown to be negative and a chest radiograph was normal. It is presumed that the brain lesions were formed by P. westermani approximately 30 years ago. 相似文献
136.
F. van de Wetering J. Hulshof K. Posthuma P. Harrewijn R. Goldbach D. Peters 《Entomologia Experimentalis et Applicata》1998,88(1):9-15
Feeding behavior and scar production of male and female F. occidentalis (Pergande) (Thysanoptera: Thripidae) were studied in relation to transmission of tomato spotted wilt tospovirus (TSWV). Electrical penetration graph (EPG) analysis showed that females feed more frequently and intensively than males. The feeding intensity, reflected by silvery scar production and studied by an image analysis system, demonstrated that females induced more numerous scars than males. At the same time, males transmitted TSWV with a higher efficiency than females, indicating that TSWV transmission and scar production are not positively correlated. Furthermore, males produced significantly more local lesions of TSWV than females. These quantitative differences in scar production and transmission of TSWV can be explained by the lower mobility and higher consumption rate of females. The influence of the sex-ratio on crop damage and virus transmission, and thus to the spread of TSWV, is emphasized. 相似文献
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138.
Seasonal changes in tropical forests are difficult to measure from the ground, especially in areas of high species diversity and low phenological synchrony. Satellite images, which integrate individual tree canopies and cover a large spatial extent, facilitate tests for stand-level canopy phenology. Variability in near-infrated radiance (TM bands 4 and 5) of several distinct vegetation types was used to detect seasonal changes in a series of three Landsat Thematic Mapper (TM) images from the wet season to the dry season in Marabá, Brazil (eastern Amazon basin). Despite different atmospheric and instrumental conditions among the images, spectral changes were distinguishable. A phenological process (leaf aging, leaf drop, water stress) was determined from the spectral changes for each vegetation type. Changes in the spectral properties suggest that during the dry season, upland terra firme forest increased the rate of leaf exchange and some riparian vegetation was deciduous. Terra firme forest that had been altered by penetration of fires from nearby pastures increased in leaf biomass over a 14-month period. This study shows that a time series of images can provide information on temporal changes in primary vegetation and guide field studies to investigate seasonal changes that may not be detectable from the ground. 相似文献
139.
Field experiments were performed in Southern Finland on fine sand and organic soil in 1990 and 1991 to study carrot roots. Fall ploughed land was loosened by rotary harrowing to a depth of 20 cm or compacted under moist conditions to a depth of 25–30 cm by three passes of adjacent wheel tracks with a tractor weighing 3 Mg, in April were contiguously applied across the plot before seed bed preparation. Sprinkler irrigation (30 mm) was applied to fine sand when moisture in the 0–15 cm range of soil depth was 50% of plant-available water capacity. For root sampling, polyvinyl chloride (PVC) cylinders (30 × 60 cm) were installed in the rows of experimental plots after sowing, and removed at harvest. Six carrot plants were grown in each of in these soil colums in situ in the field.Fine root length and width were quantified by image analysis. Root length density (RLD) per plant was 0.2–1.0 cm cm-3 in the 0–30 cm range. The fibrous root system of one carrot had total root lengths of 130–150 m in loose fine sand and 180–200 m in compacted fine sand. More roots were observed in irrigated than non-irrigated soils. In the 0–50 cm range of organic soil, 230–250 m of root length were removed from loosened organic soils and 240–300 m from compacted soils. Specific root surface area (surface area divided by dry root weight) of a carrot fibrous root system averaged 1500–2000 cm2 g-1. Root length to weight ratios of 250–350 m g-1 effectively compare with the ratios of other species.Fibrous root growth was stimulated by soil compaction or irrigation to a depth of 30 cm, in both the fine sand and organic soils, suggesting better soil water supply in compacted than in loosened soils. Soil compaction increased root diameters more in fine sand than it did in organic soil. Most of the root length in loosened soils (fine sand 90%, organic soil 80%) and compacted soils (fine sand 80%, organic soil 75%) was composed of roots with diameters of approximately 0.15 mm. With respect to dry weight, length, surface area and volume of the fibrous root system, all the measurements gave significant resposes to irrigation and soil compaction. Total root volumes in the 0–50 cm of soil were 4.3 cm3 and 9.8 cm3 in loosened fine sand and organic soils, respectively, and 6.7 cm3 and 13.4 cm3 in compacted sand and organic soils, respectively. In fine sand, irrigation increased the volume from 4.8 to 6.3 cm3. 相似文献
140.
Summary Glomerulocyte cellulosic bundles ofPolyzoa vesiculiphora were investigated by microdiffraction and high-resolution electron microscopy. In each bundle, hundreds of cellulose microfibrils, having a rectangular cross-sectional shape, are packed regularly with their 0.6 nm lattice planes parallel to each other. Lattice images reveal that the 0.6 nm plane is parallel to the longer edge of the cross section which is similar to the lattice organization of cellulose with a squarish cross section inValonia spp. More interestingly, all the microfibrils in a bundle have the same directionality of crystallographic c-axis, which suggests that the biosynthesis of the microfibrils within particular bundle occurs unidirectionally. 相似文献