270 research outputs found
A dataset of 30-meter annual vegetation phenology indicators (1985–2015) in urban areas of the conterminous United States
Fine-resolution satellite observations show great potential for characterizing seasonal and annual dynamics of vegetation phenology in urban domains, from local to regional and global scales. However, most previous studies were conducted using coarse or moderate resolution data, which are inadequate for characterizing the spatiotemporal dynamics of vegetation phenology in urban domains. In this study, we produced an annual vegetation phenology dataset in urban ecosystems for the conterminous United States (US), using all available Landsat images on the Google Earth Engine (GEE) platform. First, we characterized the long-term mean seasonal pattern of phenology indicators of the start of season (SOS) and the end of season (EOS), using a double logistic model. Then, we identified the annual variability of these two phenology indicators by measuring the difference of dates when the vegetation index in a specific year reaches the same magnitude as its long-term mean. The derived phenology indicators agree well with in-situ observations from PhenoCam network and Harvard Forest. Comparing with results derived from the moderate resolution imaging spectroradiometer (MODIS) data, our Landsat derived phenology indicators can provide more spatial details. Also, temporal trends of phenology indicators (e.g., SOS) derived from Landsat and MODIS are consistent overall, but the Landsat derived results from 1985 have a longer temporal span compared to MODIS from 2001. In general, there is a spatially explicit pattern of phenology indicators from the North to the South in cities in the conterminous US, with an overall advanced SOS in the past three decades. The derived phenology product in the US urban domains at the national level is of great use for urban ecology studies for its fine spatial resolution (30 m) and long temporal span (30 years). The data are available at https://doi.org/10.6084/m9.figshare.7685645.v2
Model for Estimation Urban Transportation Supply-Demand Ratio
The paper establishes an estimation model of urban transportation supply-demand ratio (TSDR) to quantitatively describe the conditions of an urban transport system and to support a theoretical basis for transport policy-making. This TSDR estimation model is supported by the system dynamic principle and the VENSIM (an application that simulates the real system). It was accomplished by long-term observation of eight cities’ transport conditions and by analyzing the estimated results of TSDR from fifteen sets of refined data. The estimated results indicate that an urban TSDR can be classified into four grades representing four transport conditions: “scarce supply,” “short supply,” “supply-demand balance,” and “excess supply.” These results imply that transport policies or measures can be quantified to facilitate the process of ordering and screening them
DocStormer: Revitalizing Multi-Degraded Colored Document Images to Pristine PDF
For capturing colored document images, e.g. posters and magazines, it is
common that multiple degradations such as shadows, wrinkles, etc., are
simultaneously introduced due to external factors. Restoring multi-degraded
colored document images is a great challenge, yet overlooked, as most existing
algorithms focus on enhancing color-ignored document images via binarization.
Thus, we propose DocStormer, a novel algorithm designed to restore
multi-degraded colored documents to their potential pristine PDF. The
contributions are: firstly, we propose a "Perceive-then-Restore" paradigm with
a reinforced transformer block, which more effectively encodes and utilizes the
distribution of degradations. Secondly, we are the first to utilize GAN and
pristine PDF magazine images to narrow the distribution gap between the
enhanced results and PDF images, in pursuit of less degradation and better
visual quality. Thirdly, we propose a non-parametric strategy, PFILI, which
enables a smaller training scale and larger testing resolutions with acceptable
detail trade-off, while saving memory and inference time. Fourthly, we are the
first to propose a novel Multi-Degraded Colored Document image Enhancing
dataset, named MD-CDE, for both training and evaluation. Experimental results
show that the DocStormer exhibits superior performance, capable of revitalizing
multi-degraded colored documents into their potential pristine digital
versions, which fills the current academic gap from the perspective of method,
data, and task
Endogenous hormone and nutritional ingredient of pendulous characteristics of Cunninghamia lanceolata var. Luotian
Cunninghamia lanceolata var. Luotian (herein, Luotian), a natural variety of Cunninghamia lanceolata (Chinese fir, herein Lanceolata), shows great potential for agricultural protection short-period and high-density plantations because of its narrow, pointed, tower-shaped crowns, thin braches and older drooping branches that die naturally at 6-7 years old. The physiological mechanisms of the pendulousness and the natural death of the branches are still unclear. To investigate these mechanisms, phytohormone levels and nutritional ingredients of different positions of branches in Luotian and Lanceolata were determined. Phytohormone analyses showed that IAA and ZR played critical functions on the branch initial growth, and that GA3 was related to bending of branches. Meanwhile, ABA may enhance abscission of the branches in Luotian. Nutritional ingredient analyses showed that the accumulation of nutritional ingredients in Luotian and Lanceolata were consistent with the morphology of their branches. An integrated analysis implied that phytohormones had a strong influence on pendulous characteristics by interacting with other factors. This study helps to elucidate the mechanism governing the pendulous trait and provides theoretical basis and technical support for its cultivation, introduction, plantation management and genetic improvement
Tumor-directed gene therapy in mice using a composite nonviral gene delivery system consisting of the piggyBac transposon and polyethylenimine
<p>Abstract</p> <p>Background</p> <p>Compared with viral vectors, nonviral vectors are less immunogenic, more stable, safer and easier to replication for application in cancer gene therapy. However, nonviral gene delivery system has not been extensively used because of the low transfection efficiency and the short transgene expression, especially <it>in vivo</it>. It is desirable to develop a nonviral gene delivery system that can support stable genomic integration and persistent gene expression <it>in vivo</it>. Here, we used a composite nonviral gene delivery system consisting of the <it>piggyBac </it>(PB) transposon and polyethylenimine (PEI) for long-term transgene expression in mouse ovarian tumors.</p> <p>Methods</p> <p>A recombinant plasmid PB [Act-RFP, HSV-tk] encoding both the herpes simplex thymidine kinase (HSV-tk) and the monomeric red fluorescent protein (mRFP1) under PB transposon elements was constructed. This plasmid and the PBase plasmid were injected into ovarian cancer tumor xenografts in mice by <it>in vivo </it>PEI system. The antitumor effects of HSV-tk/ganciclovir (GCV) system were observed after intraperitoneal injection of GCV. Histological analysis and TUNEL assay were performed on the cryostat sections of the tumor tissue.</p> <p>Results</p> <p>Plasmid construction was confirmed by PCR analysis combined with restrictive enzyme digestion. mRFP1 expression could be visualized three weeks after the last transfection of pPB/TK under fluorescence microscopy. After GCV admission, the tumor volume of PB/TK group was significantly reduced and the tumor inhibitory rate was 81.96% contrasted against the 43.07% in the TK group. Histological analysis showed that there were extensive necrosis and lymphocytes infiltration in the tumor tissue of the PB/TK group but limited in the tissue of control group. TUNEL assays suggested that the transfected cells were undergoing apoptosis after GCV admission <it>in vivo</it>.</p> <p>Conclusion</p> <p>Our results show that the nonviral gene delivery system coupling PB transposon with PEI can be used as an efficient tool for gene therapy in ovarian cancer.</p
Brown adipose tissue is the key depot for glucose clearance in microbiota depleted mice
Acknowledgements This work was supported by the National Natural Science Foundation of China (92057206), the KC Wong Education Foundation, as well as grants from the ‘1000 talents’ recruitment program, a PIFI professorial fellowship from CAS and a Wolfson merit professorship from the UK Royal Society, all to J.R.S. We are grateful to all the members of the Molecular Energetics Group for their support and discussion of the results. We would like to thank Peter Thomson and Marina Stamatiou for technical assistance with the DLW measurements.Peer reviewedPublisher PD
Increased Variation in Body Weight and Food Intake Is Related to Increased Dietary Fat but Not Increased Carbohydrate or Protein in Mice
Funding This study was funded by the National Key R&D Program of China (2019YFA0801900) to JS and the Postdoctoral Innovation Fund (2021) to YW. The original diet exposure experiment was funded by the Chinese Academy of Sciences Strategic Program (XDB13030100). JS was also supported during this work by a PIFI professorial fellowship from CAS and a Wolfson merit award from the UK Royal Society. CORRECTION article Front. Nutr., 21 October 2022 Sec. Nutrition and Metabolism https://doi.org/10.3389/fnut.2022.1049766 Corrigendum: Increased variation in body weight and food intake is related to increased dietary fat but not increased carbohydrate or protein in micePeer reviewedPublisher PD
A single nucleotide mutation in the dual-oxidase 2 (DUOX2) gene causes some of the panda's unique metabolic phenotypes
This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB13030100 and XDB29020000), the Creative Research Group Project of National Natural Science Foundation of China (31821001), the Key Project of the Chinese Academy of Sciences (QYZDB-SSW-SMC047), the National Key Research and Development Program of China (2018YFC2000500), the Chinese Academy of Sciences President's International Fellowship Initiative Postdoctoral Fellowship (to A.M.R.) and the President's International Fellowship Initiative Professorial and Wolfson Merit Award (to J.R.S.).Peer reviewedPublisher PD
Microbiota Depletion Impairs Thermogenesis of Brown Adipose Tissue and Browning of White Adipose Tissue
This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB13030000) and Natural Science Foundation of China (NSFC; 91649108), the Chinese Academy of Sciences-Novo Nordisk Foundation, as well as grants from the Chinese Academy of Sciences “1000 Talents” recruitment program and a “Great-Wall Professorship” from the Chinese Academy of Sciences-Novo Nordisk Foundation. J.R.S. was also supported by a Wolfson merit professorship from The UK Royal Society. We are grateful to all of the members of the Molecular Energetics Group for their support and discussion of the results. We would like to thank Dr. Jia and Dr. Sun from the Core Facility for Protein Research from the Institute of Biophysics, Chinese Academy of Sciences for flow cytometry, and Peter Thomson and Marina Samatiou for technical assistance with the DLW measurements.Peer reviewedPublisher PD
Effects of dietary macronutrients and body composition on glucose homeostasis in mice
Funding This work was supported by the Chinese Academy of Sciences Strategic Programs (XDA12030209 and XDB13030100), the 1000 Talents Program and a Wolfson Merit Award to J.R.SPeer reviewedPublisher PD
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