282 research outputs found
Changes in plant species richness distribution in Tibetan alpine grasslands under different precipitation scenarios
Species richness is the core of biodiversity-ecosystem functioning (BEF) research. Nevertheless, it is difficult to accurately predict changes in plant species richness under different climate scenarios, especially in alpine biomes. In this study, we surveyed plant species richness from 2009 to 2017 in 75 alpine meadows (AM), 199 alpine steppes (AS), and 71 desert steppes (DS) in the Tibetan Autonomous Region, China. Along with 20 environmental factors relevant to species settlement, development, and survival, we first simulated the spatial pattern of plant species richness under current climate conditions using random forest modelling. Our results showed that simulated species richness matched well with observed values in the field, showing an evident decrease from meadows to steppes and then to deserts. Summer precipitation, which ranked first among the 20 environmental factors, was further confirmed to be the most critical driver of species richness distribution. Next, we simulated and compared species richness patterns under four different precipitation scenarios, increasing and decreasing summer precipitation by 20% and 10%, relative to the current species richness pattern. Our findings showed that species richness in response to altered precipitation was grassland-type specific, with meadows being sensitive to decreasing precipitation, steppes being sensitive to increasing precipitation, and deserts remaining resistant. In addition, species richness at low elevations was more sensitive to decreasing precipitation than to increasing precipitation, implying that droughts might have stronger influences than wetting on species composition. In contrast, species richness at high elevations (also in deserts) changed slightly under different precipitation scenarios, likely due to harsh physical conditions and small species pools for plant recruitment and survival. Finally, we suggest that policymakers and herdsmen pay more attention to alpine grasslands in central Tibet and at low elevations where species richness is sensitive to precipitation changes
AMLP:Adaptive Masking Lesion Patches for Self-supervised Medical Image Segmentation
Self-supervised masked image modeling has shown promising results on natural
images. However, directly applying such methods to medical images remains
challenging. This difficulty stems from the complexity and distinct
characteristics of lesions compared to natural images, which impedes effective
representation learning. Additionally, conventional high fixed masking ratios
restrict reconstructing fine lesion details, limiting the scope of learnable
information. To tackle these limitations, we propose a novel self-supervised
medical image segmentation framework, Adaptive Masking Lesion Patches (AMLP).
Specifically, we design a Masked Patch Selection (MPS) strategy to identify and
focus learning on patches containing lesions. Lesion regions are scarce yet
critical, making their precise reconstruction vital. To reduce
misclassification of lesion and background patches caused by unsupervised
clustering in MPS, we introduce an Attention Reconstruction Loss (ARL) to focus
on hard-to-reconstruct patches likely depicting lesions. We further propose a
Category Consistency Loss (CCL) to refine patch categorization based on
reconstruction difficulty, strengthening distinction between lesions and
background. Moreover, we develop an Adaptive Masking Ratio (AMR) strategy that
gradually increases the masking ratio to expand reconstructible information and
improve learning. Extensive experiments on two medical segmentation datasets
demonstrate AMLP's superior performance compared to existing self-supervised
approaches. The proposed strategies effectively address limitations in applying
masked modeling to medical images, tailored to capturing fine lesion details
vital for segmentation tasks
HAT: Hybrid Attention Transformer for Image Restoration
Transformer-based methods have shown impressive performance in image
restoration tasks, such as image super-resolution and denoising. However, we
find that these networks can only utilize a limited spatial range of input
information through attribution analysis. This implies that the potential of
Transformer is still not fully exploited in existing networks. In order to
activate more input pixels for better restoration, we propose a new Hybrid
Attention Transformer (HAT). It combines both channel attention and
window-based self-attention schemes, thus making use of their complementary
advantages. Moreover, to better aggregate the cross-window information, we
introduce an overlapping cross-attention module to enhance the interaction
between neighboring window features. In the training stage, we additionally
adopt a same-task pre-training strategy to further exploit the potential of the
model for further improvement. Extensive experiments have demonstrated the
effectiveness of the proposed modules. We further scale up the model to show
that the performance of the SR task can be greatly improved. Besides, we extend
HAT to more image restoration applications, including real-world image
super-resolution, Gaussian image denoising and image compression artifacts
reduction. Experiments on benchmark and real-world datasets demonstrate that
our HAT achieves state-of-the-art performance both quantitatively and
qualitatively. Codes and models are publicly available at
https://github.com/XPixelGroup/HAT.Comment: Extended version of HA
Diagnosis and phylogenetic analysis of Orf virus from goats in China: a case report
<p>Abstract</p> <p>Background</p> <p>Orf virus (ORFV) is the etiological agent of contagious pustular dermatitis and is the prototype of the genus Parapoxvirus (PPV). It causes a severe exanthematous dermatitis that afflicts domestic and wild small ruminants.</p> <p>Case presentation</p> <p>In the present study, an outbreak of proliferative dermatitis in farmed goats. The presence of ORFV in tissue scrapings from the lips was confirmed by B2L gene polymerase chain reaction (PCR) amplification. The molecular characterization of the ORFV was performed using PCR amplification, DNA sequencing and phylogenetic analysis of the B2L gene.</p> <p>Conclusion</p> <p>The results of this investigation indicated that the outbreak was caused by infection with an ORFV that was closely related genetically to Nantou (DQ934351), which was isolated from the Tai wan province of China and Hoping (EU935106), which originated from South Korea in 2008. This is the first report of the phylogenetic analysis of ORFV from goats in China.</p
Characteristics and drivers of plant C, N, and P stoichiometry in Northern Tibetan Plateau grassland
Understanding vegetation C, N, and P stoichiometry helps us not only to evaluate biogeochemical cycles and ecosystem functions but also to predict the potential impact of environmental change on ecosystem processes. The foliar C, N, and P stoichiometry in Northern Tibetan grasslands, especially the controlling factors, has been highlighted in recent years. In this study, we have collected 340 plant samples and 162 soil samples from 54 plots in three grassland types, with the purpose of evaluating the foliar C, N, and P stoichiometry and underlying control factors in three grassland types along a 1,500-km east-to-west transect in the Northern Tibetan Plateau. Our results indicated that the averaged foliar C, N, and P concentrations were 425.9 ± 15.8, 403.4 ± 22.2, and 420.7 ± 30.7 g kg−1; 21.7 ± 2.9, 19.0 ± 2.3, and 21.7 ± 5.2 g kg−1; and 1.71 ± 0.29, 1.19 ± 0.16, and 1.59 ± 0.6 g kg−1 in the alpine meadow (AM), alpine steppe (AS), and desert steppe (DS) ecosystems, respectively. The foliar C and N ratios were comparable, with values of 19.8 ± 2.8, 20.6 ± 1.9, and 19.9 ± 5.8 in the AM, AS, and DS ecosystems, respectively. Both the C/P and N/P ratios are the lowest in the AM ecosystem, with values of 252.2 ± 32.6 and 12.8 ± 1.3, respectively, whereas the highest values of 347.3 ± 57.0 and 16.2 ± 3.2 were obtained in the AS ecosystem. In contrast, the soil C, N, C/P, and N/P values decreased from the AM to DS ecosystem. Across the whole transects, leaf C, N, and P stoichiometry showed no obvious trend, but soil C and N concentrations showed an increasing trend, and soil P concentrations showed a decreasing trend with the increasing longitude. Based on the general linear model analysis, the vegetation type was the dominant factor controlling the leaf C, N, and P stoichiometry, accounting for 42.8% for leaf C, 45.1% for leaf N, 35.2% for leaf P, 52.9% for leaf C/N, 39.6% for leaf C/P, and 48.0% for leaf N/P; the soil nutrients and climate have relatively low importance. In conclusion, our results supported that vegetation type, rather than climatic variation and soil nutrients, are the major determinants of north Tibet grassland leaf stoichiometry
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