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1.
Coupled climate-carbon cycle models suggest that Amazon forests are vulnerable to both long- and short-term droughts, but satellite observations showed a large-scale photosynthetic green-up in intact evergreen forests of the Amazon in response to a short, intense drought in 2005. These findings suggest that Amazon forests, although threatened by human-caused deforestation and fire and possibly by more severe long-term droughts, may be more resilient to climate changes than ecosystem models assume. 相似文献
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Julia Antongiovanni Joselevitch Thiago Henrique Moroni Vargas Lidia Hildebrand Pulz Karine Germano Cadrobbi Greice Cestari Huete Adriana Tomoko Nishiya Silvia Regina Kleeb José Guilherme Xavier Ricardo De Francisco Strefezzi 《Veterinary and comparative oncology》2023,21(3):401-405
Mast cell tumour (MCT) is one of the most frequent skin tumours in dogs. Due to their unpredictable biological behaviour, MCTs often cause several therapeutic frustrations, leading to investigation regarding prognostic markers. Lysyl oxidase (LOX) is an enzyme that promotes extracellular matrix stability and contributes to cell migration, angiogenesis and epithelial-mesenchymal transition. Its expression positively correlates with poor prognoses in several human and canine mammary cancers. The aim of this study was to characterise the immunohistochemical expression of LOX in MCT samples and compare it with histological grading and post-surgical survival. Twenty-six tumours were submitted to immunohistochemistry for LOX expression evaluation. All samples were positive for LOX, with variable percentages of cytoplasmic and nuclear positivity. Cytoplasmic positivity was significantly higher in high-grade MCTs (P = .0297). Our results indicate that high expression of cytoplasmic LOX in neoplastic mast cells is an indicator of poor prognosis for canine cutaneous MCTs. 相似文献
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The morphological maturation of the acinar cells of the guinea pig pancreas during post-natal development was characterized morphometrically by determining the intracytoplasmic accumulation of rough endoplasmic reticulum (RER) and zymogen granules. The following results were obtained for the period analysed, i.e., from 2 to 70 days of post-natal life: (a) the acinar cell volume increased by 210% (P < 0.01); (b) the mostly cisternal RER occupied more than 30% of the cytoplasm at any age studied and their total volume and surface in the cell were increased by 300 and 534% (P < 0.01), respectively; (c) maturation in the morphological pattern of the RER was observed; (d) the mean number of zymogen granules per cell increased from 261 at 2 days to 422 at 70 days (P < 0.01), while their mean diameter increased from 0.52 to 0.94 micron (P < 0.01) during the same period; (e) these increases in granule number and size were responsible for a 500% (P < 0.01) increase in total volume from 2 to 70 days and for a 304% increase (P < 0.01) in total surface from 2 to 35 days; (f) the RER and the zymogen granules together occupied 44, 54, 55 and 57% of the cytoplasm at 2, 14, 35 and 70 days of age, respectively. We conclude that although the pancreatic acinar cells of the guinea pig are morphologically well differentiated at 2 days of age, with the cytoplasm already showing a large amount of RER and zymogen granules, they are still immature. Morphological maturation of the acinar cell occurs during the first months of post-natal life and is characterized by a substantial gain in cell volume and intracytoplasmic accumulation of RER and zymogen granules, which significantly increase of both their absolute volume and total surface, with a higher growth rate being observed during the period from 2 to 14 days of post-natal life. 相似文献
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The objective of the present study was to analyse allometrically the growth of the Syrian golden hamster pancreas during days 2 to 70 of postnatal development. Body and pancreatic mass were determined, followed by stereological determination of the absolute volume of each morphological compartment of the pancreas. The marked pancreatic growth, by 4360%, was due to an increase in the absolute volume of all morphological compartments, mainly the acini which showed an increase of 10 431%. Bivariate allometric analysis of pancreatic mass and morphological compartmental volume in relation to body mass gain showed: (1) a biphasic pattern for pancreatic mass, acinar volume, excretory duct volume and stromal volume, with the first phase being observed from 2 to 21 days of age and the second from 21 to 70 days of age, with allometry coefficients of 1.537-0.513, 1.770-0.543, 1.651-0.506 and 0.967-0.258, respectively, and (2) a monophasic pattern from 2 to 70 days for intercalated duct volume and islet volume, with allometry coefficients of 0.913 and 1.727, respectively. These results show that during the growth of the pancreas in relation to that of the body some structures - acini and excretory ducts - follow the growth pattern of the organ, while others - intercalated ducts and islets - show a different pattern. This may be related to the genetic growth characteristics of each compartment itself or to some relationship between compartments during some stage of the ontogenetic development of this organ. 相似文献
5.
C R Teixeira S C Rahal R S Volpi R Taga T M Cestari J M Granjeiro L C Vulcano M A Correa 《Veterinary and comparative orthopaedics and traumatology》2007,20(4):269-276
Tibia segmental defect healing in sheep were clinically, radiographically and histologically evaluated. Twelve young sheep aged four to five months were divided into two groups, G1 and G2. A 3.5 cm long segmental defect was created in the right tibial diaphysis with maintenance of the periosteum. The bone defects in both groups were stabilized with a bone plate combined with a titanium cage. In G1 the cage was filled with pieces of autologous cortical bone graft. In G2 it was filled with a composite biomaterial which consisted of inorganic bovine bone, demineralized bovine bone, a pool of bovine bone morphogenetic proteins bound to absorbable ultra-thin powdered hydroxyapatiteand bone-derived denaturized collagen. Except for one G1 animal, all of them showed normal limb function 60 days after surgery. Radiographic examination showed initial formation of periosteal callus in both groups at osteo-tomy sites, over the plate or cage 15 days postoperatively. At 60 and 90 days callus remodeling occurred. Histological and morphometric analysis at 90 days after surgery showed that the quantity of implanted materials in G1 and G2 were similar, and the quantity of new bone formation was less (p = 0.0048) and more immature in G1 than G2, occupying 51 +/- 3.46% and 62 +/- 6.26% of the cage space, respectively. These results suggest that the composite biomaterial tested was a good alternative to autologous cortical bone graft in this experimental ovine tibial defect. However, additional evaluation is warranted prior to its clinical usage. 相似文献
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Nerinéia Dalfollo Ribeiro Skarlet De Marco Steckling Sandra Maria Maziero Maykon Júnior da Silva Greice Rosana Kläsener Cleiton Renato Casagrande 《Euphytica》2017,213(12):290
Genetically superior common bean lines will be efficiently selected with the use of more precise experimental statistics. The objectives of this study were to evaluate the experimental precision of grain yield and primary grain yield components in experiments to register common bean cultivars and identify more appropriate statistics for the selection of genetically superior common bean lines. For this purpose, 21 experiments were performed in a randomized block design in southern Brazil. A total of 156 common bean genotypes of the Mesoamerican and Andean gene pool were assessed between 1998 and 2015. Experimental precisions of grain yield and primary grain yield components were evaluated using 11 statistics. Grain yield, number of pods per plant, number of grains per pod, and mass of 100 grains were evaluated with greater experimental precision by the F-test value for genotype, heritability, coefficient of relative variation, and selective accuracy. Mass of 100 grains presented the highest experimental precision among the traits evaluated in this study. The F-test value for genotype, heritability, coefficient of relative variation, and selective accuracy allow the selection of common bean lines with genetic superiority for grain yield and primary grain yield components. Selective accuracy is the most appropriate statistic to select common bean lines with genetic superiority for grain yield and is recommended for breeding programs. 相似文献
8.
Amaral Carneiro Greice Walcher Magdalena Baric Sanja 《European journal of plant pathology / European Foundation for Plant Pathology》2022,162(1):247-255
European Journal of Plant Pathology - Recently, Cadophora luteo-olivacea has been reported as a post-harvest pathogen of side rot of apple (Malus domestica) in Latvia, and of pear (Pyrus communis)... 相似文献
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Kim A. Franklin Pamela L. Nagler Edward P. Glenn Francisco Molina-Freaner Alfredo R. Huete 《Biological conservation》2006,127(1):62-71
Bufflelgrass (Pennisetum ciliare syn. Cenchrus ciliaris) is an African grass that has been widely introduced in subtropical arid regions of the world to improve rangelands for cattle production. However, it can have a negative effect on the diversity of native plant communities. Buffelgrass was introduced to Sonora, Mexico in the 1970s as a means to bolster the cattle industry. “Desmonte,” the process by which native desert vegetation is removed in preparation for buffelgrass seeding, alters the land surface such that buffelgrass plots are easily detectable from aerial and Landsat satellite images. We estimated the extent of conversion to buffelgrass in a 1,850,000 ha area centered on Hermosillo, from MSS and TM images from 1973, 1983, 1990 and 2000. We then compared the relative above-ground productivity of buffelgrass to native vegetation using Normalized Difference Vegetation Index values (NDVI) from Landsat and Moderate Resolution Imaging Spectrometer (MODIS) satellite sensor systems. Buffelgrass pastures have increased from just 7700 ha in 1973 to over 140,000 ha in 2000. Buffelgrass pastures now cover 8% of the land surface in the study area. Buffelgrass pastures have lower net primary productivity, estimated by MODIS NDVI values, than unconverted desert land. The desmonte process removes trees and shrubs, while the buffelgrass plantings are often sparse, leading to an apparent net loss in net primary production from land conversion. We recommend that the desmonte process be discontinued until its efficacy and safety for native ecosystems can be established, and that a comprehensive plan for preserving biodiversity while accomodating economic development be established for this region of the Sonoran Desert in Mexico. 相似文献
10.
Interpreting vegetation indices 总被引：17，自引：0，他引：17
Remotely sensed spectral vegetation indices are widely used and have benefited numerous disciplines interested in the assessment of biomass, water use, plant stress, plant health and crop production. The successful use of these indices requires knowledge of the units of the input variables used to form the indices, and an understanding of the manner in which the external environment and the architectural aspects of a vegetation canopy influence and alter the computed index values. Although vegetation indices were developed to extract the plant signal only, the soil background, moisture condition, solar zenith angle, view angle, as well as the atmosphere, alter the index values in complex ways. The nature of these problems are explored both in an empirical and in a theoretical sense, and suggestions are offered for the effective use and interpretation of vegetation indices. 相似文献