1,462 research outputs found
Disease-Associated Mutations Prevent GPR56-Collagen III Interaction
GPR56 is a member of the adhesion G protein-coupled receptor (GPCR) family. Mutations in GPR56 cause a devastating human brain malformation called bilateral frontoparietal polymicrogyria (BFPP). Using the N-terminal fragment of GPR56 (GPR56N) as a probe, we have recently demonstrated that collagen III is the ligand of GPR56 in the developing brain. In this report, we discover a new functional domain in GPR56N, the ligand binding domain. This domain contains four disease-associated mutations and two N-glycosylation sites. Our study reveals that although glycosylation is not required for ligand binding, each of the four disease-associated mutations completely abolish the ligand binding ability of GPR56. Our data indicates that these four single missense mutations cause BFPP mostly by abolishing the ability of GPR56 to bind to its ligand, collagen III, in addition to affecting GPR56 protein surface expression as previously shown
Evaluation of land surface models in reproducing satellite derived leaf area index over the high-latitude northern hemisphere. Part II: Earth system models
PublishedJournal ArticleLeaf Area Index (LAI) is a key parameter in the Earth System Models (ESMs) since it strongly affects land-surface boundary conditions and the exchange of matter and energy with the atmosphere. Observations and data products derived from satellite remote sensing are important for the validation and evaluation of ESMs from regional to global scales. Several decades' worth of satellite data products are now available at global scale which represents a unique opportunity to contrast observations against model results. The objective of this study is to assess whether ESMs correctly reproduce the spatial variability of LAI when compared with satellite data and to compare the length of the growing season in the different models with the satellite data. To achieve this goal we analyse outputs from 11 coupled carbon-climate models that are based on the set of new global model simulations planned in support of the IPCC Fifth Assessment Report. We focus on the average LAI and the length of the growing season on Northern Hemisphere over the period 1986-2005. Additionally we compare the results with previous analyses (Part I) of uncoupled land surface models (LSMs) to assess the relative contribution of vegetation and climatic drivers on the correct representation of LAI. Our results show that models tend to overestimate the average values of LAI and have a longer growing season due to the later dormancy. The similarities with the uncoupled models suggest that representing the correct vegetation fraction with the associated parameterizations; is more important in controlling the distribution and value of LAI than the climatic variables. © 2013 by the authors.This work was funded by the European Commission’s 7th Framework Programme under Grant Agreements number 238366 (GREENCYCLESII project) and 282672 (EMBRACE project)
Spatiotemporally consistent global dataset of the GIMMS Normalized Difference Vegetation Index (PKU GIMMS NDVI) from 1982 to 2022
Global products of remote sensing Normalized Difference Vegetation
Index (NDVI) are critical to assessing the vegetation dynamic and its
impacts and feedbacks on climate change from local to global scales. The
previous versions of the Global Inventory Modeling and Mapping Studies
(GIMMS) NDVI product derived from the Advanced Very High Resolution
Radiometer (AVHRR) provide global biweekly NDVI data starting from the
1980s, being a reliable long-term NDVI time series that has been widely
applied in Earth and environmental sciences. However, the GIMMS NDVI
products have several limitations (e.g., orbital drift and sensor
degradation) and cannot provide continuous data for the future. In this
study, we presented a machine learning model that employed massive
high-quality global Landsat NDVI samples and a data consolidation method to
generate a new version of the GIMMS NDVI product, i.e., PKU GIMMS NDVI
(1982–2022), based on AVHRR and Moderate-Resolution Imaging
Spectroradiometer (MODIS) data. A total of 3.6 million Landsat NDVI samples
that were well spread across the globe were extracted for vegetation biomes
in all seasons. The PKU GIMMS NDVI exhibits higher accuracy than its
predecessor (GIMMS NDVI3g) in terms of R2 (0.97 over 0.94), root mean
squared error (RMSE: 0.05 over 0.09), mean absolute error (MAE: 0.03 over
0.07), and mean absolute percentage error (MAPE: 9 % over 20 %).
Notably, PKU GIMMS NDVI effectively eliminates the evident orbital drift and
sensor degradation effects in tropical areas. The consolidated PKU GIMMS
NDVI has a high consistency with MODIS NDVI in terms of pixel value (R2 = 0.956, RMSE = 0.048, MAE = 0.034, and MAPE = 6.0 %) and global
vegetation trend (0.9×10-3 yr−1). The PKU GIMMS NDVI
product can potentially provide a more solid data basis for global change
studies. The theoretical framework that employs Landsat data samples can
facilitate the generation of remote sensing products for other land surface
parameters. The PKU GIMMS NDVI product is open access and available under a Creative Commons Attribution 4.0 License at https://doi.org/10.5281/zenodo.8253971 (Li et al., 2023).</p
Bayesian dissection for genetic architecture of traits associated with nitrogen utilization efficiency in rice
Nitrogen is one of the key important nutrients in rice production. High rice grain yield is greatly dependent upon economic nitrogen input and genetic factors. In order to locate quantitative loci for traits associated with nitrogen utilization efficiency in rice, F9 recombinant inbred lines derived from a Korean tongil type Dasanbyeo and a Chinese japonica variety TR22183 was genetically designed. The six traits of interest were observed on 155 RILs, along with 105 SSR and 103 STS markers. Bayesian model selection technique was used to dissect genetic architecture for traits of interest. A total of 28 main-effect QTLs and 23 pairs of epistatic QTLs were detected for traits associated with nitrogen utilization efficiency. The proportions of phenotypic variation explained by the detected QTLs ranged from 0.09 to 16.90% and from 0.19 to 12.76% for main-effect and epistatic QTLs, respectively. Sixteen of main-effect QTLs interacted with nitrogen level. One pleiotropic QTL was found, governing simultaneously nitrogen dry matter production efficiency and Nitrogen grain production efficiency
Preferential loss of a polymorphic RIZ allele in human hepatocellular carcinoma
The RIZ (PRDM2) locus commonly undergoes loss of heterozygosity (LOH) and maps within the minimal deleted region on 1p36 in hepatocellular carcinoma (HCC). Although peptide-altering mutations of RIZ are rare in HCC, the RIZ1 product is commonly lost in HCC and has tumour suppressive activities. Here, we analysed RIZ gene mutations and LOH in HCC, breast cancer, familial melanoma, colon cancer, and stomach cancer. We found 7 polymorphisms but no mutations. By analysing the Pro704-deletion polymorphism, we detected LOH of RIZ in 31 of 79 (39%) informative HCC cases, 11 of 47 (23%) colon cancer cases, 8 of 43 (19%) breast cancer cases, 8 of 66 (12%) stomach cancer cases. Importantly, loss of the Pro704+allele was found in 74% of the 31 LOH positive HCC cases (P< 0.01), indicating a preferential loss and hence a stronger tumour suppressor role for this allele compared to the P704−allele. In addition, the Pro704+allele was found to be more common in Asians (0.61) than Caucasians (0.42) (P = 0.0000), suggesting an interesting link between gene polymorphisms and potential differences in tumour incidence between racial groups. © 2001 Cancer Research Campaign http://www.bjcancer.co
Tachyonic Inflation in a Warped String Background
We analyze observational constraints on the parameter space of tachyonic
inflation with a Gaussian potential and discuss some predictions of this
scenario. As was shown by Kofman and Linde, it is extremely problematic to
achieve the required range of parameters in conventional string
compactifications. We investigate if the situation can be improved in more
general compactifications with a warped metric and varying dilaton. The
simplest examples are the warped throat geometries that arise in the vicinity
of of a large number of space-filling D-branes. We find that the parameter
range for inflation can be accommodated in the background of D6-branes wrapping
a three-cycle in type IIA. We comment on the requirements that have to be met
in order to realize this scenario in an explicit string compactification.Comment: Latex, JHEP class, 20 pages, 4 figures. v2: references added, small
error in section 7 corrected, published versio
Detecting Change in the Urban Road Environment Along a Route Based on Traffic Sign and Crossroad Data
Occurrences of traffic signs that belong to certain sign categories and occurrences of crossroads of various topologies are utilized in detecting change in the urban road environment that moves past an ego-car. Three urban environment types, namely downtown, residential and industrial/commercial areas, are considered in the study and changes between these are to be detected. In the preparatory phase, the ego-car is used for traffic sign and crossroads data collection. In the application phase, the ego-car hosts an advanced driver assistance system (ADAS) that captures and analyzes images of the road environment and computes the required input data to the proposed road environment detection (RoED) subsystem. A statistical inference method relying on the minimum description length (MDL) principle was applied to the change detection problem at hand. The above occurrences along a route are seen as a realization of an inhomogeneous marked Poisson process. Page-Hinkley change detectors tuned to empirical data were set to work to detect change in the urban road environment. The process and the quality of the change detection are demonstrated via examples from three urban settlements in Hungary.
Document type: Part of book or chapter of boo
Effect of waste materials on acoustical properties of semi-dense asphalt mixtures
Among the urban societal burdens rolling noise generation from tire pavement interaction and urban waste stand apart. Many urban waste materials can be used in pavements with comparable mechanical performance. Noise-related pavement characteristics such as porosity, sound absorption and surface texture, were measured for semi-dense low noise pavement mixtures using urban waste materials namely: recycled concrete aggregates, crumb rubber, polyethylene terephthalate and polyethylene. The results show that the use of these materials is a viable sustainable option for low noise pavements, however that may affect the noise reduction properties. With values around 0.2 at 1000 Hz, the sound absorption of all the mixtures is relatively low and the use of mean profile depth (MPD) alone is not enough to characterize the noise reduction properties. Surface texture was altered in different degrees depending on the waste material used. The results presented can aid in policy pertaining to noise abatement and waste reduction
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