2,830 research outputs found

    Scattering theory for the Schr\"odinger-Debye System

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    We study the Schr\"odinger-Debye system over Rd\mathbb{R}^d iu_t+\frac 12\Delta u=uv,\quad \mu v_t+v=\lambda |u|^2 and establish the global existence and scattering of small solutions for initial data in several function spaces in dimensions d=2,3,4d=2,3,4. Moreover, in dimension d=1d=1, we prove a Hayashi-Naumkin modified scattering result.Comment: 22 page

    THE PHARMACOLOGICAL EFFECT OF STILBENES ISOLATED FROM KANGAROO ISLAND PROPOLIS ON SIRT-1 ENZYME ACTIVITY

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    Objective: Resveratrol, a trihydroxystilbene, has been claimed to be a potent activator to SIRT-1 enzyme activity, which in turn could have a useful future application in the management of many chronic conditions such as metabolic syndrome and obesity. A group of novel tetrahydroxystilbene derivatives were isolated from Kangaroo Island propolis in Australia. Due to its structural similarities with resveratrol, the aim of this research was to explore the activity of Kangaroo Island prenylated stilbenes on SIRT-1 enzyme.Methods: In vitro fluorometry measurement of SIRT-1 enzyme activity using SIRT-1 assay kit (Cayman®).Results: None of the tested compounds had shown any activation to SIRT-1 enzyme, on contrary, they produced mild inhibition to the enzyme. Compound 3 (C20H22O4, 3,5,4'-trihydroxy-3'-methoxy-2-prenyl-E-stilbene) was the most potent inhibitor.Conclusion: Compound 3, in addition to compounds 2, 4, and 6 are candidate compounds for further investigation. A discussion of the results as well as the contradictory results in the literature has been presented in this article.Â

    DNA-based identification of Australian varieties of wheat and barley

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    Established and supported under the Australian Government’s Cooperative Research Centre Progra

    Mapping Topics in 100,000 Real-life Moral Dilemmas

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    Moral dilemmas play an important role in theorizing both about ethical norms and moral psychology. Yet thought experiments borrowed from the philosophical literature often lack the nuances and complexity of real life. We leverage 100,000 threads -- the largest collection to date -- from Reddit's r/AmItheAsshole to examine the features of everyday moral dilemmas. Combining topic modeling with evaluation from both expert and crowd-sourced workers, we discover 47 finer-grained, meaningful topics and group them into five meta-categories. We show that most dilemmas combine at least two topics, such as family and money. We also observe that the pattern of topic co-occurrence carries interesting information about the structure of everyday moral concerns: for example, the generation of moral dilemmas from nominally neutral topics, and interaction effects in which final verdicts do not line up with the moral concerns in the original stories in any simple way. Our analysis demonstrates the utility of a fine-grained data-driven approach to online moral dilemmas, and provides a valuable resource for researchers aiming to explore the intersection of practical and theoretical ethics.Comment: To be published in ICWSM 202

    FPGA-accelerated machine learning inference as a service for particle physics computing

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    New heterogeneous computing paradigms on dedicated hardware with increased parallelization, such as Field Programmable Gate Arrays (FPGAs), offer exciting solutions with large potential gains. The growing applications of machine learning algorithms in particle physics for simulation, reconstruction, and analysis are naturally deployed on such platforms. We demonstrate that the acceleration of machine learning inference as a web service represents a heterogeneous computing solution for particle physics experiments that potentially requires minimal modification to the current computing model. As examples, we retrain the ResNet-50 convolutional neural network to demonstrate state-of-the-art performance for top quark jet tagging at the LHC and apply a ResNet-50 model with transfer learning for neutrino event classification. Using Project Brainwave by Microsoft to accelerate the ResNet-50 image classification model, we achieve average inference times of 60 (10) milliseconds with our experimental physics software framework using Brainwave as a cloud (edge or on-premises) service, representing an improvement by a factor of approximately 30 (175) in model inference latency over traditional CPU inference in current experimental hardware. A single FPGA service accessed by many CPUs achieves a throughput of 600--700 inferences per second using an image batch of one, comparable to large batch-size GPU throughput and significantly better than small batch-size GPU throughput. Deployed as an edge or cloud service for the particle physics computing model, coprocessor accelerators can have a higher duty cycle and are potentially much more cost-effective.Comment: 16 pages, 14 figures, 2 table

    Two nonrecombining sympatric forms of the human malaria parasite Plasmodium ovale occur globally.

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    BACKGROUND: Malaria in humans is caused by apicomplexan parasites belonging to 5 species of the genus Plasmodium. Infections with Plasmodium ovale are widely distributed but rarely investigated, and the resulting burden of disease is not known. Dimorphism in defined genes has led to P. ovale parasites being divided into classic and variant types. We hypothesized that these dimorphs represent distinct parasite species. METHODS: Multilocus sequence analysis of 6 genetic characters was carried out among 55 isolates from 12 African and 3 Asia-Pacific countries. RESULTS: Each genetic character displayed complete dimorphism and segregated perfectly between the 2 types. Both types were identified in samples from Ghana, Nigeria, São Tomé, Sierra Leone, and Uganda and have been described previously in Myanmar. Splitting of the 2 lineages is estimated to have occurred between 1.0 and 3.5 million years ago in hominid hosts. CONCLUSIONS: We propose that P. ovale comprises 2 nonrecombining species that are sympatric in Africa and Asia. We speculate on possible scenarios that could have led to this speciation. Furthermore, the relatively high frequency of imported cases of symptomatic P. ovale infection in the United Kingdom suggests that the morbidity caused by ovale malaria has been underestimated

    Resolved velocity profiles of galactic winds at Cosmic Noon

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    We study the kinematics of the interstellar medium (ISM) viewed "down the barrel" in 20 gravitationally lensed galaxies during Cosmic Noon (z=1.53.5z=1.5 - 3.5). We use moderate-resolution spectra (R4000R\sim4000) from Keck/ESI and Magellan/MagE to spectrally resolve the ISM absorption in these galaxies into \sim10 independent elements and use double Gaussian fits to quantify the velocity structure of the gas. We find that the bulk motion of gas in this galaxy sample is outflowing, with average velocity centroid \left=-141 km\,s1^{-1} (±111\pm111 km\,s1^{-1} scatter) measured with respect to the systemic redshift. 16 out of the 20 galaxies exhibit a clear positive skewness, with a blueshifted tail extending to 500\sim -500 km\,s1^{-1}. We examine scaling relations in outflow velocities with galaxy stellar mass and star formation rate (SFR), finding correlations consistent with a momentum-driven wind scenario. Our measured outflow velocities are also comparable to those reported for FIRE-2 and TNG50 cosmological simulations at similar redshift and galaxy properties. We also consider implications for interpreting results from lower-resolution spectra. We demonstrate that while velocity centroids are accurately recovered, the skewness, velocity width, and probes of high velocity gas (e.g., v95v_{95}) are subject to large scatter and biases at lower resolution. We find that R1700R\gtrsim1700 is required for accurate results for the gas kinematics of our sample. This work represents the largest available sample of well-resolved outflow velocity structure at z>2z>2, and highlights the need for good spectral resolution to recover accurate properties.Comment: 42 pages, 37 figures (including appendix), Accepted for publication, Ap

    A sedge plant as the source of Kangaroo Island propolis rich in prenylated p-coumarate ester and stilbenes

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    AbstractPropolis samples from Kangaroo Island, South Australia, were investigated for chemical constituents using high-field nuclear magnetic resonance spectral profiling. A type of propolis was found containing a high proportion of prenylated hydroxystilbenes. Subsequently, the botanical origin of this type of propolis was identified using a beehive propolis depletion method and analysis of flora. Ligurian honey bees, Apis mellifera ligustica Spinola, were found to produce propolis from resin exuded by the Australian native sedge plant Lepidosperma sp. Montebello (Cyperaceae). The plants, commonly known as sword sedge, were found to have resin that matched with the propolis samples identified as the most abundant propolis type on the island containing C- and O-prenylated tetrahydroxystilbenes (pTHOS) in addition to a small amount of prenylated p-coumarate. The isolation of five pTHOS not previously characterized are reported: (E)-4-(3-methyl-2-buten-1-yl)-3,4′,5-trihydroxy-3′-methoxystilbene, (E)-2,4-bis(3-methyl-2-buten-1-yl)-3,3′,4′,5-tetrahydroxystilbene, (E)-2-(3-methyl-2-buten-1-yl)-3-(3-methyl-2-butenyloxy)-3′,4′,5-trihydroxystilbene, (E)-2,6-bis(3-methyl-2-buten-1-yl)-3,3′,5,5′-tetrahydroxystilbene and (E)-2,6-bis(3-methyl-2-buten-1-yl)-3,4′,5-trihydroxy-3′-methoxystilbene. A National Cancer Institute 60 human cell line anticancer screen of three of these compounds showed growth inhibitory activity. The large Australasian genus Lepidosperma is identified as a valuable resource for the isolation of substances with medicinal potential

    p63 Expression Defines a Lethal Subset of Muscle-Invasive Bladder Cancers

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    <div><h3>Background</h3><p>p63 is a member of the p53 family that has been implicated in maintenance of epithelial stem cell compartments. Previous studies demonstrated that p63 is downregulated in muscle-invasive bladder cancers, but the relationship between p63 expression and survival is not clear.</p> <h3>Methodology/Principal Findings</h3><p>We used real-time PCR to characterize p63 expression and several genes implicated in epithelial-to-mesenchymal transition (EMT) in human bladder cancer cell lines (n = 15) and primary tumors (n = 101). We correlated tumor marker expression with stage, disease-specific (DSS), and overall survival (OS). Expression of E-cadherin and p63 correlated directly with one another and inversely with expression of the mesenchymal markers Zeb-1, Zeb-2, and vimentin. Non-muscle-invasive (Ta and T1) bladder cancers uniformly expressed high levels of E-cadherin and p63 and low levels of the mesenchymal markers. Interestingly, a subset of muscle-invasive (T2–T4) tumors maintained high levels of E-cadherin and p63 expression. As expected, there was a strongly significant correlation between EMT marker expression and muscle invasion (p<0.0001). However, OS was shorter in patients with muscle-invasive tumors that retained p63 (p = 0.007).</p> <h3>Conclusions/Significance</h3><p>Our data confirm that molecular markers of EMT are elevated in muscle-invasive bladder cancers, but interestingly, retention of the “epithelial” marker p63 in muscle-invasive tumors is associated with a worse outcome.</p> </div
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