2,790 research outputs found

    A Dnn-Ensemble Method for Error Reduction and Training Data Selection in Dnn based Modeling

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    Deep neural networks (DNNs) have been widely adopted in modeling electromagnetic compatibility (EMC) problems, but the training data acquisition is usually time-consuming through various simulators. This paper presents a powerful approach using an ensemble of DNN s to effectively reduce the training data size in DNN-based modeling problems. A batch of training data with the largest uncertainties is selected using active learning through the variance among the ensemble of DNNs. Subsequently, a greedy sampling algorithm is applied to select a data subset using diversity. Thus, the proposed method can achieve both uncertainty and diversity in data selection. By averaging the outputs of the DNN ensemble, the prediction error can be further reduced. Simple mathematical functions are used to validate the proposed method, and a high-dimensional strip line modeling problem also demonstrates the effectiveness of this DNN-ensemble approach. The proposed method is task agnostic and can be used in other surrogate modeling problems with DNN s

    A preexisting rare PIK3CA e545k subpopulation confers clinical resistance to MEK plus CDK4/6 inhibition in NRAS melanoma and is dependent on S6K1 signaling

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    Combined MEK and CDK4/6 inhibition (MEKi + CDK4i) has shown promising clinical outcomes in patients with NRAS- mutant melanoma. Here, we interrogated longitudinal biopsies from a patient who initially responded to MEKi + CDK4i therapy but subsequently developed resistance. Whole-exome sequencing and functional validation identified an acquired PIK3CA E545K mutation as conferring drug resistance. We demonstrate that PIK3CA E545K preexisted in a rare subpopulation that was missed by both clinical and research testing, but was revealed upon multiregion sampling due to PIK3CA E545K being nonuniformly distributed. This resistant population rapidly expanded after the initiation of MEKi + CDK4i therapy and persisted in all successive samples even after immune checkpoint therapy and distant metastasis. Functional studies identified activated S6K1 as both a key marker and specific therapeutic vulnerability downstream of PIK3CA E545K -induced resistance. These results demonstrate that difficult-to-detect preexisting resistance mutations may exist more often than previously appreciated and also posit S6K1 as a common downstream therapeutic nexus for the MAPK, CDK4/6, and PI3K pathways. SIGNIFICANCE: We report the first characterization of clinical acquired resistance to MEKi + CDK4i, identifying a rare preexisting PIK3CA E545K subpopulation that expands upon therapy and exhibits drug resistance. We suggest that single-region pretreatment biopsy is insufficient to detect rare, spatially segregated drug-resistant subclones. Inhibition of S6K1 is able to resensitize PIK3CA E545K -expressing NRAS-mutant melanoma cells to MEKi + CDK4i. Ā© 2018 AAC

    The fermion dynamical symmetry model for the even--even and even--odd nuclei in the Xe--Ba region

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    The even--even and even--odd nuclei 126^{126}Xe-132^{132}Xe and 131^{131}Ba-137^{137}Ba are shown to have a well-realized SO8āŠƒSO6āŠƒSO3SO_8 \supset SO_6 \supset SO_3 fermion dynamical symmetry. Their low-lying energy levels can be described by a unified analytical expression with two (three) adjustable parameters for even--odd (even--even) nuclei that is derived from the fermion dynamical symmetry model. Analytical expressions are given for wavefunctions and for E2E2 transition rates that agree well with data. The distinction between the FDSM and IBM SO6SO_6 limits is discussed. The experimentally observed suppression of the the energy levels with increasing SO5SO_5 quantum number Ļ„\tau can be explained as a perturbation of the pairing interaction on the SO6SO_6 symmetry, which leads to an SO5SO_5 Pairing effect for SO6SO_6 nuclei.Comment: submitted to Phys. Rev. C, LaTeX, 31 pages, 8 figures with postscript files available on request at [email protected]

    Impacts of sulfide exposure on juvenile Tor tambroides (Bleeker, 1854): behavioral responses and mortality

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    Construction of hydroelectric reservoirs had been reported to be the cause of increased sulfide levels resulting from the decomposition of organic matter. As more dams are being built, a better understanding of the impact of sulfide on indigenous species is required. In Sarawak, Tor tambroides is a highly valuable and sought after species which is facing declining population. This study aimed to determine the behavioral responses and mortality of juvenile T. tambroides exposed to sulfide. The three exposure experiments were gradual sulfide exposure, gradual sulfide exposure under lowering DO and gradual sulfide exposure under lowering pH. A modified flow-through design was used to expose the juveniles in containers to sulfide of different concentrations. Actual total sulfide in containers was determined according to standard method. During the duration of the experiment, behavioral responses, DO and pH were monitored. Experimental results show that negative controls recorded no behavioral response and no mortality was observed in all control experiments. However, under all sulfide exposure experiments, the juveniles displayed at least one behavioral response in the progression of huddling together, aquatic surface respiration, loss of equilibrium and turning upside down except for the gradual sulfide exposure experiment where no response was observed with the lowest total sulfide concentration tested (82 Āµg L-1). For all three exposure experiments, faster responses and mortalities were observed when the concentration of sulfide increased. The LC50 at 6th hour of exposure was estimated to be 306 Āµg/L total sulfide (138 Āµg L-1 H2S) at 95% confidence level. Sulfide toxicity was found to be highly related to the decreasing DO and pH levels attributable to intensifying toxicity which led to mortality

    Pseudo-Goldstone Boson Effects in Top-Antitop Productions at High Energy Hadron Colliders and Testing Technicolor Models

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    We study the top quark pair production process p+p(anti-p)-->top+antitop in various kinds of technicolor (TC) models at the Fermilab Tevatron Run II and the CERN LHC. The s-channel neutral pseudo-Goldstone bosons (PGB's) contribute dominately to the production amplitudes from its coupling to the gluons through the triangle loops of techniquarks and the top quark. Cross sections in different TC models with s-channel PGB contributions are calculated. It is shown that the PGB effects can be experimentally tested and different TC models under consideration can be distinguished at the LHC. Therefore, the p+p-->top+antitop process at the LHC provides feasible tests of the TC models.Comment: 10 pages in RevTex and 4 PS-files for the figures. Paramemter range is changed, and some references are added. Version for publication in Phys. Rev.

    Postpartum depression in mothers and fathers: a structural equation model

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    open access articleBackground Post-partum depression (PPD) is a growing mental health concern worldwide. There is little evidence in the Chinese context of the relationship between paternal PPD and maternal PPD. Given the growing global concerns this relationship requires further exploration. Methods A survey was conducted with 950 total couples from March 2017 to December 2018. The study was conducted using a standardized questionnaire that included basic demographic information, information on the relationship between the mother-in-law and daughter-in-law, marital satisfaction (both maternal and paternal), and PPD symptoms. Structural Equation Modelling (SEM) analysis was used to explore the underlying mechanism for PPD symptoms in mothers and fathers. Results In 4.4% of the couples both the wife and the husband showed depressive symptoms. Maternal marital satisfaction showed a significant mediating effect on paternal PPD (B = -0.114, pā€‰<ā€‰0.01), and there was a direct effect of maternal PPD on paternal PPD (Bā€‰=ā€‰0.31, pā€‰<ā€‰0.001). Conclusions This is the first study to investigate the possible correlation between maternal PPD, mother-in-law and daughter-in-law relationship satisfaction, maternal marital satisfaction, paternal marital satisfaction, and paternal PPD. It is important for future PPD interventions to target both maternal and paternal mental health, as well as the mechanisms identified that can lead to PPD

    Arsenic and Fluoride Exposure in Drinking Water: Childrenā€™s IQ and Growth in Shanyin County, Shanxi Province, China

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    BACKGROUND: Recently, in a cross-sectional study of 201 children in Araihazar, Bangladesh, exposure to arsenic (As) in drinking water has been shown to lower the scores on tests that measure childrenā€™s intellectual function before and after adjustment for sociodemographic features. OBJECTIVES: We investigated the effects of As and fluoride exposure on childrenā€™s intelligence and growth. METHODS: We report the results of a study of 720 children between 8 and 12 years of age in rural villages in Shanyin county, Shanxi province, China. The children were exposed to As at concentrations of 142 Ā± 106 Ī¼g/L (medium-As group) and 190 Ā± 183 Ī¼g/L (high-As group) in drinking water compared with the control group that was exposed to low concentrations of As (2 Ā± 3 Ī¼g/L) and low concentrations of fluoride (0.5 Ā± 0.2 mg/L). A study group of children exposed to high concentrations of fluoride (8.3 Ā± 1.9 mg/L) but low concentrations of As (3 Ā± 3 Ī¼g/L) was also included because of the common occurrence of elevated concentrations of fluoride in groundwater in our study area. A standardized IQ (intelligence quotient) test was modified for children in rural China and was based on the classic Ravenā€™s test used to determine the effects of these exposures on childrenā€™s intelligence. A standardized measurement procedure for weight, height, chest circumference, and lung capacity was used to determine the effects of these exposures on childrenā€™s growth. RESULTS: The mean IQ scores decreased from 105 Ā± 15 for the control group, to 101 Ā± 16 for the medium-As group (p < 0.05), and to 95 Ā± 17 for the high-As group (p < 0.01). The mean IQ score for the high-fluoride group was 101 Ā± 16 and significantly different from that of the control group (p < 0.05). Children in the control group were taller than those in the high-fluoride group (p < 0.05); weighed more than the those in the high-As group (p < 0.05); and had higher lung capacity than those in the medium-As group (p < 0.05). CONCLUSIONS: Childrenā€™s intelligence and growth can be affected by high concentrations of As or fluoride. The IQ scores of the children in the high-As group were the lowest among the four groups we investigated. It is more significant that high concentrations of As affect childrenā€™s intelligence. It indicates that arsenic exposure can affect childrenā€™s intelligence and growth
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