RESUMO
Vegetation dynamics is essential for characterizing surface biogeophysical parameters. Speeds of vegetation development and senescence are well documented, however, the effects of vegetation growth rates on surface parameters during different growth stages remains unclear. By using such methods as trend analyses and correlation analyses, this study examines the variations and interactive relationships of leaf area index (LAI) and surface parameters including Albedo, evapotranspiration (ET), and land surface temperature (LST), derived from Moderate Resolution Imaging Spectroradiometer (MODIS), during the intra-growing season (April-October, GS) on the Mongolian Plateau (MP). Generally, LAI exhibited a significant upward trend across GS months. Significant changes in VLAI (the difference in LAI between 2 consecutive months) in April-May and September-October indicated that the vegetation change rates were accelerated in the early GS (April-June) and late GS (September-October). The effect of vegetation activity on surface parameters varies over time and space. The effects of VLAI on the speed of surface parameters were inconsistent during the intra-GS. As a result of the significant changes in LAI, VET (the difference in ET between 2 consecutive months) displayed a significant upward trend during the early GS but a significant downward trend during the late GS. With acceleration of vegetation activity, the effects of VET and VAlbedo (the difference in Albedo between 2 consecutive months) on LST could offset each other at different stages of the GS. In addition, the effect of VLAI on the speed of surface parameters varied significantly by vegetation types. Our findings imply that clarifying the impact of vegetation activity on surface parameters at different growth stages can advance our understanding of vegetation responses and feedbacks to climate change.
Assuntos
Desenvolvimento Vegetal , Mongólia , Estações do Ano , Monitoramento Ambiental , Temperatura , Ecossistema , Folhas de Planta/crescimento & desenvolvimento , Plantas , Mudança ClimáticaRESUMO
Optical coherence tomography angiography (OCTA) for blood vessel 3-D structure imaging suffers from blood vessel projection artifacts/tail artifacts when using a long decorrelation time (e.g., repeat B-scan acquisition in regular OCTA) or loss of micro vessel signal when using a short decorrelation time. In this work, we developed an adaptive first-order field autocorrelation function (g1) analysis-based technique to suppress the projection artifacts under macro vessels while enhancing the dynamic signal of micro vessels. The proposed method is based on the differences of the decorrelation rate and the phase variations of g1 between the vessel voxels and the artifacts regions. A short or long decorrelation time was applied to obtain the dynamic index of the projection artifacts region or the blood vessel region, respectively. Compared to the slab subtraction-based post-image processing-based techniques, the proposed approach addresses this problem on a physical basis and shows the ability to suppress the projection artifacts while enhancing the detection of the micro vessels.
RESUMO
BACKGROUND: Dermatophagoides pteronyssinus is a common allergen causing allergic diseases in China. The aim of this study was to evaluate the efficacy and safety of D. pteronyssinus extracts produced by Peking Union Medical College Hospital (PUMCH) for the skin prick test (SPT) in the diagnosis of D. pteronyssinus allergy. METHODS: A total of 910 subjects with allergic diseases were prescribed D. pteronyssinus SPT and specific sIgE (sIgE) test among the Outpatients of Department of Allergy, PUMCH from August 10, 2015 to August 30, 2017. Receiver operating characteristic curve (ROC) analysis was performed according to the results of D. pteronyssinus-sIgE detection. The accuracy of D. pteronyssinus extracts used for SPT in the diagnosis of D. pteronyssinus allergy was evaluated under different cutoff values. Adverse events after SPT were recorded to evaluate safety. RESULTS: There were 796 and 618 subjects in the full analysis set (FAS) and the per protocol set (PPS), respectively. The areas under the curve of FAS and PPS were 0.871 and 0.873, respectively. According to the ROC of PPS, the optimal and 95% specificity diagnostic cutoff values of D. pteronyssinus SPT mean wheal diameter were 3.25 and 3.75 mm, respectively. No adverse events occurred. CONCLUSION: The extracts of D. pteronyssinus for SPT were simple, highly accurate, and safe and should be considered for recommendation in the clinical diagnosis of D. pteronyssinus allergy.
Assuntos
Dermatophagoides pteronyssinus , Hipersensibilidade , Animais , Humanos , Antígenos de Dermatophagoides , Alérgenos , Testes Cutâneos/métodosRESUMO
A novel delayed anaphylactic reaction to red meat, associated with tick bites and IgE antibodies against galactose-α-1, 3-galactose (α-gal), was reported in 2009 in the US, Australia and Europe. In this case, serum specific IgE to galactose-α-1, 3-galactose (>100 kU/L) and IgE to multiple non-primate mammalian proteins were positive. However, the pathogenesis of this disease remains unclear. We report the first case in Asia of delayed anaphylactic reaction to red meat, which was induced by bites from the hard tick, Hematophagous ixodidae. We confirmed the increased concentration of IgE reactive epitopes in non-primate mammalian organs, which may be rich in α-gal proteins in lymphatic and endothelial tissues. All confirmed ticks associated with this disorder in the literature and in our case belonged to the hard tick family. We hypothesize that hard tick saliva is enriched with blood-type substances, such as oligosaccharides, from the non-primate mammal victim's blood after days to weeks of blood sucking, which sensitizes humans through the injection route while blood sucking.
RESUMO
The study aims to investigate fungal community structures and dynamic changes in forest soil lignocellulose-degrading process. rRNA gene clone libraries for the samples collected in different stages of lignocellulose degradation process were constructed and analyzed. A total of 26 representative RFLP types were obtained from original soil clone library, including Mucoromycotina (29.5%), unclassified Zygomycetes (33.5%), Ascomycota (32.4%), and Basidiomycota (4.6%). When soil accumulated with natural lignocellulose, 16 RFLP types were identified from 8-day clone library, including Basidiomycota (62.5%), Ascomycota (36.1%), and Fungi incertae sedis (1.4%). After enrichment for 15 days, identified 11 RFLP types were placed in 3 fungal groups: Basidiomycota (86.9%), Ascomycota (11.5%), and Fungi incertae sedis (1.6%). The results showed richer, more diversity and abundance fungal groups in original forest soil. With the degradation of lignocellulose, fungal groups Mucoromycotina and Ascomycota decreased gradually, and wood-rotting fungi Basidiomycota increased and replaced the opportunist fungi to become predominant group. Most of the fungal clones identified in sample were related to the reported lignocellulose-decomposing strains. Understanding of the microbial community structure and dynamic change during natural lignocellulose-degrading process will provide us with an idea and a basis to construct available commercial lignocellulosic enzymes or microbial complex.