47 research outputs found

    Distributed Contingency Analysis over Wide Area Network among Dispatch Centers

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    Traditionally, a regional dispatch center uses the equivalent method to deal with external grids, which fails to reflect the interactions among regions. This paper proposes a distributed N-1 contingency analysis (DCA) solution, where dispatch centers join a coordinated computation using their private data and computing resources. A distributed screening method is presented to determine the Critical Contingency Set (DCCS) in DCA. Then, the distributed power flow is formulated as a set of boundary equations, which is solved by a Jacobi-Free Newton-GMRES (JFNG) method. During solving the distributed power flow, only boundary conditions are exchanged. Acceleration techniques are also introduced, including reusing preconditioners and optimal resource scheduling during parallel processing of multiple contingencies. The proposed method is implemented on a real EMS platform, where tests using the Southwest Regional Grid of China are carried out to validate its feasibility.Comment: 5 pages, 6 figures, 2017 IEEE PES General Meetin

    Plio-Pleistocene establishment of Irtysh River in Junggar, Northwest China: implications for Siberian-Arctic river system evolution and resulting climate impact

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    The influence of Siberian freshwater input to the Arctic Ocean on Northern Hemisphere ice-sheet expansions remains poorly known due to the incomplete geologic record of Siberian-Arctic river systems during the late Pliocene. The Irtysh River is a major Siberian river, rising from the Altay Mountains, northwestern China, and flowing 4,282 km before joining the Ob River. Here, we present new field evidence and chronological data from a combination of cosmogenic 21Ne and 26Al/10Be measurements that constrain the establishment of the Irtysh River to ca. 2.77+0.39/-0.33 Ma. These first quantitative chronological results, together with previous sedimentological, geomorphological, and geochemical evidence, support a young Siberian-Arctic river system. Its coincidence with the late Pliocene ice-sheet expansions in the Northern Hemisphere implies a profound impact of Siberian freshwater input to the Arctic on the major ice advances that significantly affected global oceanographic and climatic systems

    Mid-Miocene cosmogenic upper limit for 10Be/21Ne burial

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    Cosmogenic nuclide burial dating provides an alternative method for sediment dating, and the combination of radionuclide 10Be with noble gas isotope 21Ne would theoretically extend the burial dating range up to around 15 Ma ago, which endows 10Be/21Ne pair with huge potential in middle-Miocene sediment dating. Especially in the magnetostratigraphic studies of the Cenozoic sedimentary strata, the 10Be/21Ne pair could be expected to provide absolute age marker when the well-dated volcanic ash layer or bedded mammalian fossils are absent. However, the validity and accuracy of the 10Be/21Ne burial dating when used close to its limiting middle Miocene ages has not been assessed in case study. Here, we show our dating results of the sedimentary stratum samples, which deposited at the same bedding of the Vertebrate fossils of Platybelodon tongxinensis that offer an independent age constraint between 12 and 15 Ma. The 10Be/21Ne analyses yielded a mean burial age of 13.25 ± 0.33 Ma, which agrees well with the paleontological proxy, and the MSWD value of 0.66 indicates the good agreement of the apparent dispersion of six aliquots data with their individual measurement errors. In view of the extended applicable dating range of 10Be/21Ne pair, it is promising in providing absolute age marker or valuable chronological information for a variety of fields in Earth science and beyond

    De novo variation in ARID1B gene causes Coffin-Siris syndrome 1 in a Chinese family with excessive early-onset high myopia

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    Abstract Coffin-Siris syndrome (CSS) is a rare autosomal dominant inheritance disorder characterized by distinctive facial features, hypoplasia of the distal phalanx or nail of the fifth and additional digits, developmental or cognitive delay of varying degree, hypotonia, hirsutism/hypertrichosis, sparse scalp hair and varying kind of congenital anomalies. CSS can easily be misdiagnosed as other syndromes or disorders with a similar clinical picture because of their genetic and phenotypic heterogeneity. We describde the genotype-phenotype correlation of one patient from a healthy Chinese family with a novel genotype underlying CSS, who was first diagnosed in the ophthalmology department as early-onset high myopia (eoHM). Comprehensive ophthalmic tests as well as other systemic examinations were performed on participants to confirm the phenotype. The genotype was identified using whole exome sequencing, and further verified the results among other family members by Sanger sequencing. Real-time quantitative PCR (RT-qPCR) technology was used to detect the relative mRNA expression levels of candidate genes between proband and normal family members. The pathogenicity of the identified variant was determined by The American College of Medical Genetics and Genomics (ACMG) guidelines. STRING protein-protein interactions (PPIs) network analysis was used to detect the interaction of candidate gene-related proteins with high myopia gene-related proteins. The patient had excessive eoHM, cone-rod dystrophy, coarse face, excessive hair growth on the face, sparse scalp hair, developmental delay, intellectual disability, moderate hearing loss, dental hypoplasia, patent foramen ovale, chronic non-atrophic gastritis, bilateral renal cysts, cisterna magna, and emotional outbursts with aggression. The genetic assessment revealed that the patient carries a de novo heterozygous frameshift insertion variant in the ARID1B c.3981dup (p.Glu1328ArgfsTer5), which are strongly associated with the typical clinical features of CSS patients. The test results of RT-qPCR showed that mRNA expression of the ARID1B gene in the proband was approximately 30% lower than that of the normal control in the family, suggesting that the variant had an impact on the gene function at the level of mRNA expression. The variant was pathogenic as assessed by ACMG guidelines. Analysis of protein interactions in the STRING online database revealed that the ARID1A protein interacts with the high myopia gene-related proteins FGFR3, ASXL1, ERBB3, and SOX4, whereas the ARID1A protein antagonizes the ARID1B protein. Therefore, in this paper, we are the first to report a de novo heterozygous frameshift insertion variant in the ARID1B gene causing CSS with excessive eoHM. Our study extends the genotypic and phenotypic spectrums for ARID1B-CSS and supplies evidence of significant association of eoHM with variant in ARID1B gene. As CSS has high genetic and phenotypic heterogeneity, our findings highlight the importance of molecular genetic testing and an interdisciplinary clinical diagnostic workup to avoid misdiagnosis as some disorders with similar manifestations of CSS

    In Situ Thermal Reduction of Graphene Nanosheets Based Poly(methyl methacrylate) Nanocomposites with Effective Reinforcements

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    The incorporation of graphene nanosheets (GNSs) into a polymer matrix can effectively enhance its thermal and mechanical properties. We report a facile and eco-friendly method for preparing polymer nanocomposites with homogeneously dispersed GNSs in the poly­(methyl methacrylate) (PMMA) matrix via first grafting functionalized graphene oxide (GO) using PMMA miniemulsion, then melt blending the grafted GO with PMMA matrix, and simultaneous in situ thermal reduction of GO in the matrix. The results show that the GNSs exhibit exfoliated morphology and good distribution in the obtained nanocomposites. A 37.9% enhancement in tensile strength and a 61.4% increase of Young’s modulus with respect to the polymer matrix are achieved by incorporating only 1.5 wt % GNSs loading. The experimental derived Young’s modulus agrees well with the theoretical simulation. Moreover, the storage modulus of the nanocomposites increases by 45%, while the glass transition temperature (<i>T</i><sub>g</sub>) increases by 7.5 °C at 1.5 wt % GNSs loading

    Self-reported ethnicity and genetic ancestry in relation to oral cancer and pre-cancer in Puerto Rico.

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    Hispanics are known to be an extremely diverse and genetically admixed ethnic group. The lack of methodologies to control for ethnicity and the unknown admixture in complex study populations of Hispanics has left a gap in understanding certain cancer disparity issues. Incidence rates for oral and pharyngeal cancer (OPC) in Puerto Rico are among the highest in the Western Hemisphere. We conducted an epidemiological study to examine risk and protective factors, in addition to possible genetic susceptibility components, for oral cancer and precancer in Puerto Rico.We recruited 310 Puerto Rico residents who had been diagnosed with either an incident oral squamous cell carcinoma, oral precancer, or benign oral condition. Participants completed an in-person interview and contributed buccal cells for DNA extraction. ABI Biosystem Taqman™ primer sets were used for genotyping 12 ancestry informative markers (AIMs). Ancestral group estimates were generated using maximum likelihood estimation software (LEADMIX), and additional principal component analysis was carried out to detect population substructures. We used unconditional logistic regression to assess the contribution of ancestry to the risk of being diagnosed with either an oral cancer or precancer while controlling for other potential confounders. The maximum likelihood estimates showed that study participants had a group average ancestry contribution of 69.9% European, 24.5% African, and 5.7% detectable Native American. The African and Indigenous American group estimates were significantly higher than anticipated. Neither self-identified ethnicity nor ancestry markers showed any significant associations with oral cancer/precancer risk in our study.The application of ancestry informative markers (AIMs), specifically designed for Hispanics, suggests no hidden population substructure is present based on our sampling and provides a viable approach for the evaluation and control of ancestry in future studies involving Hispanic populations
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