294 research outputs found
Using Unlabeled Data for Increasing Low-Shot Classification Accuracy of Relevant and Open-Set Irrelevant Images
In search exploration and reconnaissance tasks performed with autonomous ground vehicles an image classification capability is needed for specifically identifying targeted objects relevant classes and at the same time recognize when a candidate image does not belong to anyone of the relevant classes irrelevant images In this paper we present an open-set low-shot classifier that uses during its training a modest number less than 40 of labeled images for each relevant class and unlabeled irrelevant images that are randomly selected at each epoch of the training process The new classifier is capable of identifying images from the relevant classes determining when a candidate image is irrelevant and it can further recognize categories of irrelevant images that were not included in the training unseen The proposed low-shot classifier can be attached as a top layer to any pre-trained feature extractor when constructing a Convolutional Neural Networ
Romanian Tritium for Nuclear Fusion
The demand for tritium is expected to increase when ITER (the International Thermonuclear Experimental Reactor) begins operation in the mid-2020s. Romania is expected to detritiate its CANDU (Canada Deuterium Uranium) units at Cernavoda starting 2024, with the goal of improving radiological safety and reactor performance. Detritiation will result in a significant quantity of tritium being produced and thus Romania has an opportunity to supply tritium for fusion. In this assessment, ITER has been used as a reference device requiring tritium, as the projected tritium extraction schedule from Cernavoda aligns favourably with ITER operation. The findings suggest that Romania is capable of providing a total of 6.2 kg of tritium to ITER over its 20 year operation, generating a potential revenue of 120 M (USD) in the case of zero tritium sales. Greater involvement in future fission-fusion tritium-related activities through experience in tritium technologies is also discussed as a unique opportunity for Romania
Time Series of Magnetic Field Parameters of Merged MDI and HMI Space-Weather Active Region Patches as Potential Tool for Solar Flare Forecasting
Solar flare prediction studies have been recently conducted with the use of
Space-Weather MDI (Michelson Doppler Imager onboard Solar and Heliospheric
Observatory) Active Region Patches (SMARP) and Space-Weather HMI (Helioseismic
and Magnetic Imager onboard Solar Dynamics Observatory) Active Region Patches
(SHARP), which are two currently available data products containing magnetic
field characteristics of solar active regions. The present work is an effort to
combine them into one data product, and perform some initial statistical
analyses in order to further expand their application in space weather
forecasting. The combined data are derived by filtering, rescaling, and merging
the SMARP with SHARP parameters, which can then be spatially reduced to create
uniform multivariate time series. The resulting combined MDI-HMI dataset
currently spans the period between April 4, 1996, and December 13, 2022, and
may be extended to a more recent date. This provides an opportunity to
correlate and compare it with other space weather time series, such as the
daily solar flare index or the statistical properties of the soft X-ray flux
measured by the Geostationary Operational Environmental Satellites (GOES).
Time-lagged cross-correlation indicates that a relationship may exist, where
some magnetic field properties of active regions lead the flare index in time.
Applying the rolling window technique makes it possible to see how this
leader-follower dynamic varies with time. Preliminary results indicate that
areas of high correlation generally correspond to increased flare activity
during the peak solar cycle
A Genomic Pathway Approach to a Complex Disease: Axon Guidance and Parkinson Disease
While major inroads have been made in identifying the genetic causes of rare Mendelian disorders, little progress has been made in the discovery of common gene variations that predispose to complex diseases. The single gene variants that have been shown to associate reproducibly with complex diseases typically have small effect sizes or attributable risks. However, the joint actions of common gene variants within pathways may play a major role in predisposing to complex diseases (the paradigm of complex genetics). The goal of this study was to determine whether polymorphism in a candidate pathway (axon guidance) predisposed to a complex disease (Parkinson disease [PD]). We mined a whole-genome association dataset and identified single nucleotide polymorphisms (SNPs) that were within axon-guidance pathway genes. We then constructed models of axon-guidance pathway SNPs that predicted three outcomes: PD susceptibility (odds ratio = 90.8, p = 4.64 Ć 10ā38), survival free of PD (hazards ratio = 19.0, p = 5.43 Ć 10ā48), and PD age at onset (R2 = 0.68, p = 1.68 Ć 10ā51). By contrast, models constructed from thousands of random selections of genomic SNPs predicted the three PD outcomes poorly. Mining of a second whole-genome association dataset and mining of an expression profiling dataset also supported a role for many axon-guidance pathway genes in PD. These findings could have important implications regarding the pathogenesis of PD. This genomic pathway approach may also offer insights into other complex diseases such as Alzheimer disease, diabetes mellitus, nicotine and alcohol dependence, and several cancers
Rare deleterious germline variants and risk of lung cancer
Recent studies suggest that rare variants exhibit stronger effect sizes and might play a crucial role in the etiology of lung cancers (LC). Whole exome plus targeted sequencing of germline DNA was performed on 1045 LC cases and 885 controls in the discovery set. To unveil the inherited causal variants, we focused on rare and predicted deleterious variants and small indels enriched in cases or controls. Promising candidates were further validated in a series of 26,803 LCs and 555,107 controls. During discovery, we identified 25 rare deleterious variants associated with LC susceptibility, including 13 reported in ClinVar. Of the five validated candidates, we discovered two pathogenic variants in known LC susceptibility loci, ATM p.V2716A (Odds Ratio [OR] 19.55, 95%CI 5.04ā75.6) and MPZL2 p.I24M frameshift deletion (OR 3.88, 95%CI 1.71ā8.8); and three in novel LC susceptibility genes, POMC c.*28delT at 3ā² UTR (OR 4.33, 95%CI 2.03ā9.24), STAU2 p.N364M frameshift deletion (OR 4.48, 95%CI 1.73ā11.55), and MLNR p.Q334V frameshift deletion (OR 2.69, 95%CI 1.33ā5.43). The potential cancer-promoting role of selected candidate genes and variants was further supported by endogenous DNA damage assays. Our analyses led to the identification of new rare deleterious variants with LC susceptibility. However, in-depth mechanistic studies are still needed to evaluate the pathogenic effects of these specific alleles
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