243 research outputs found

    A New MMC Converter With Fault Blocking Capability for HVDC Interconnects

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    This work proposes a modular multilevel dc/dc converter, named the DC-MMC, that can be conveyed to interconnect HVDC systems of various or comparable voltage levels. Its key elements include: 1) bidirectional power stream; 2) step-up and step-down operation; and 3) bidirectional fault blocking like a dc electrical switch. The part of the DC-MMC is another class of bidirectional single-stage dc/dc converters using interleaved strings of fell sub modules. The DC-MMC operation is broke down and an open circle voltage control procedure that guarantees control adjust of every sub module capacitor by means of coursing air conditioning streams is proposed through fuzzy logic controller. simulation results were investigated in MATLAB programming

    Fractures of the Scapula

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    The scapula plays a critical role in the association between the upper extremity and the axial skeleton. Fractures of the scapula account for 0.4% to 1% of all fractures and have an annual incidence of approximately 10 per 100,000 inhabitants. Scapular fractures typically result from a high-energy blunt-force mechanism and are often associated with other traumatic injuries. The present review focuses on the presentation, diagnosis, and treatment of fractures of the scapula. Indications for surgical treatment of glenoid fossa, scapular neck, and scapular body fractures are presented in detail. Finally, the authors' preferred surgical technique, including positioning, approach, reduction, fixation, and post-operative management, is described

    The Spatial and Temporal Structure of Neural Activity across the Fly Brain

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    What are the spatial and temporal scales of brainwide neuronal activity? We used swept, confocally-aligned planar excitation (SCAPE) microscopy to image all cells in a large volume of the brain of adult Drosophila with high spatiotemporal resolution while flies engaged in a variety of spontaneous behaviors. This revealed neural representations of behavior on multiple spatial and temporal scales. The activity of most neurons correlated (or anticorrelated) with running and flailing over timescales that ranged from seconds to a minute. Grooming elicited a weaker global response. Significant residual activity not directly correlated with behavior was high dimensional and reflected the activity of small clusters of spatially organized neurons that may correspond to genetically defined cell types. These clusters participate in the global dynamics, indicating that neural activity reflects a combination of local and broadly distributed components. This suggests that microcircuits with highly specified functions are provided with knowledge of the larger context in which they operate

    Expression Analysis of Novel microRNAs in Rice During High Temperature Stress

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    MicroRNAs (miRNAs) are small non-coding RNAs which play an important role in regulating the genes involved in plant growth and development. Several studies showed that miRNAs are involved in plants response to different kinds of abiotic stresses also. In our previous study, temperature responsive miRNAs were predicted in O.sativa. 27 miRNAs were predicted to be novel in rice using homology search. In continuation to our previous study, expression of 14 novel miRNAs was done in shoot and root of 13 days old seedlings of five different rice cultivars using real time PCR. Expression these miRNAs was analyzed in control and high temperature stress environment. Out of 14 predicted novel miRNAs, two novel miRNAs- miR157a and miR165a showed expression in all five rice cultivars. Interestingly, miR165a showed a differential expression pattern among heat tolerant (N22, IR64 and Rasi) and susceptible (Vandana and Sampada) cultivars suggesting that it might have specific role in high temperature tolerance

    Neuronal birthdate reveals topography in a vestibular brainstem circuit for gaze stabilization

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    Across the nervous system, neurons with similar attributes are topographically organized. This topography reflects developmental pressures. Oddly, vestibular (balance) nuclei are thought to be disorganized. By measuring activity in birthdated neurons, we revealed a functional map within the central vestibular projection nucleus that stabilizes gaze in the larval zebrafish. We first discovered that both somatic position and stimulus selectivity follow projection neuron birthdate. Next, with electron microscopy and loss-of-function assays, we found that patterns of peripheral innervation to projection neurons were similarly organized by birthdate. Finally, birthdate revealed spatial patterns of axonal arborization and synapse formation to projection neuron outputs. Collectively, we find that development reveals previously hidden organization to the input, processing, and output layers of a highly conserved vertebrate sensorimotor circuit. The spatial and temporal attributes we uncover constrain the developmental mechanisms that may specify the fate, function, and organization of vestibulo-ocular reflex neurons. More broadly, our data suggest that, like invertebrates, temporal mechanisms may assemble vertebrate sensorimotor architecture

    Score-based Diffusion Models in Function Space

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    Diffusion models have recently emerged as a powerful framework for generative modeling. They consist of a forward process that perturbs input data with Gaussian white noise and a reverse process that learns a score function to generate samples by denoising. Despite their tremendous success, they are mostly formulated on finite-dimensional spaces, e.g. Euclidean, limiting their applications to many domains where the data has a functional form such as in scientific computing and 3D geometric data analysis. In this work, we introduce a mathematically rigorous framework called Denoising Diffusion Operators (DDOs) for training diffusion models in function space. In DDOs, the forward process perturbs input functions gradually using a Gaussian process. The generative process is formulated by integrating a function-valued Langevin dynamic. Our approach requires an appropriate notion of the score for the perturbed data distribution, which we obtain by generalizing denoising score matching to function spaces that can be infinite-dimensional. We show that the corresponding discretized algorithm generates accurate samples at a fixed cost that is independent of the data resolution. We theoretically and numerically verify the applicability of our approach on a set of problems, including generating solutions to the Navier-Stokes equation viewed as the push-forward distribution of forcings from a Gaussian Random Field (GRF).Comment: 26 pages, 7 figure

    Neuronal Birthdate Reveals Topography in a Vestibular Brainstem Circuit for Gaze Stabilization

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    Across the nervous system, neurons with similar attributes are topographically organized. This topography reflects developmental pressures. Oddly, vestibular (balance) nuclei are thought to be disorganized. By measuring activity in birthdated neurons, we revealed a functional map within the central vestibular projection nucleus that stabilizes gaze in the larval zebrafish. We first discovered that both somatic position and stimulus selectivity follow projection neuron birthdate. Next, with electron microscopy and loss-of-function assays, we found that patterns of peripheral innervation to projection neurons were similarly organized by birthdate. Finally, birthdate revealed spatial patterns of axonal arborization and synapse formation to projection neuron outputs. Collectively, we find that development reveals previously hidden organization to the input, processing, and output layers of a highly conserved vertebrate sensorimotor circuit. The spatial and temporal attributes we uncover constrain the developmental mechanisms that may specify the fate, function, and organization of vestibulo-ocular reflex neurons. More broadly, our data suggest that, like invertebrates, temporal mechanisms may assemble vertebrate sensorimotor architecture

    A multi-dimensional approach from seed-to-seed to understand and improve heat stress tolerance in rice

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    In changing climatic conditions, stress caused by high temperature poses a serious threat to rice cultivation. Physiological, biochemical, and molecular analysis of rice cultivars revealed that Nagina22 (N22) shows lesser reduction in chlorophyll content, net photosynthetic rate, spikelet fertility and grain yield, but increased membrane thermal stability, antioxidant enzymes activity and transpiration rate (E) at high temperature. DREB, RAB, LEA, and genes associated with hormones signalling were induced during germination, while OsFd (an iron sulphur cluster binding protein) and CWIP (cell wall integrity protein) emerged as high priority candidate genes in seedling and reproductive stages. Their function is being analysed by transgene expression and CRISPR/Cas genome editing approaches. Field screening in polyhouse, late sowing and temperature gradient chamber for 20 morpho-physiological traits indicated the importance of both yield and spikelet fertility, and photosynthesis traits. N22 showed the least Heat Susceptibility Index (HSI) for yield/plant, spikelet fertility, flag leaf SPAD and stomatal conductance, while Vandana showed the highest HSI for spikelet fertility and flag leaf temperature. QTLs for HSI of spikelet fertility were identified on chromosome 1 and HSI of yield per plant on chromosomes 1, 2, 3, 4, 7 and 8; and PV of 6% to 57% using 174 F2-3 Vandana x N22 mapping population. Simultaneously, RNAseq was performed to identify the genome wide miRNAs and transcriptome of N22 and Vandana from shoot and root after short and long duration of heat stress treatments; and recovery phase for an eQTL-guided function-related co-expression analysis to identify the putative regulators and gene regulatory networks

    Deep sequencing of small RNAs reveals ribosomal origin of microRNAs in Oryza sativa and their regulatory role in high temperature

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    MicroRNAs are small noncoding regulatory RNAs which control gene expression by mRNA degradation or translational repression. They are significant molecular players regulating important biological processes such as developmental timing and stress response. We report here the discovery of miRNAs derived from ribosomal DNA using the small RNA datasets of 16 deep sequencing libraries of rice. Twelve putative miRNAs were identified based on highly stringent criteria of novel miRNA prediction. Surprisingly, 10 putative miRNAs (mi_7403, mi_8435, mi_12675, mi_4266, mi_4758, mi_4218, mi_8200, mi_4644, mi_14291, mi_16235) originated from rDNA of rice chromosome 9. Expression analysis of putative miRNAs and their target genes in heat tolerant and susceptible rice cultivars in control and high temperature treated seedlings revealed differential regulation of rDNA derived miRNAs. This is the first report of rDNA derived miRNAs in rice which indicates their role in gene regulation during high temperature stress in plants. Further studies in this area will open new research challenges and opportunities to broaden our knowledge on gene regulation mechanisms
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