1,970 research outputs found

    Strangelet dwarfs

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    If the surface tension of quark matter is low enough, quark matter is not self bound. At sufficiently low pressure and temperature, it will take the form of a crystal of positively charged strangelets in a neutralizing background of electrons. In this case there will exist, in addition to the usual family of strange stars, a family of low-mass large-radius objects analogous to white dwarfs, which we call "strangelet dwarfs". Using a generic parametrization of the equation of state of quark matter, we calculate the mass-radius relationship of these objects.Comment: 10 pages, LaTeX, added discussion of CFL phase and strangelet pollution, version to appear in journal. arXiv admin note: text overlap with arXiv:0808.067

    Transcriptome Analyses of Tumor-Adjacent Somatic Tissues Reveal Genes Co-Expressed with Transposable Elements

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    Background: Despite the long-held assumption that transposons are normally only expressed in the germ-line, recent evidence shows that transcripts of transposable element (TE) sequences are frequently found in the somatic cells. However, the extent of variation in TE transcript levels across different tissues and different individuals are unknown, and the co-expression between TEs and host gene mRNAs have not been examined. Results: Here we report the variation in TE derived transcript levels across tissues and between individuals observed in the non-tumorous tissues collected for The Cancer Genome Atlas. We found core TE co-expression modules consisting mainly of transposons, showing correlated expression across broad classes of TEs. Despite this co-expression within tissues, there are individual TE loci that exhibit tissue-specific expression patterns, when compared across tissues. The core TE modules were negatively correlated with other gene modules that consisted of immune response genes in interferon signaling. KRAB Zinc Finger Proteins (KZFPs) were over-represented gene members of the TE modules, showing positive correlation across multiple tissues. But we did not find overlap between TE-KZFP pairs that are co-expressed and TE-KZFP pairs that are bound in published ChIP-seq studies. Conclusions: We find unexpected variation in TE derived transcripts, within and across non-tumorous tissues. We describe a broad view of the RNA state for non-tumorous tissues exhibiting higher level of TE transcripts. Tissues with higher level of TE transcripts have a broad range of TEs co-expressed, with high expression of a large number of KZFPs, and lower RNA levels of immune genes

    Построение сложных опционных стратегий с учетом предпочтений инвестора. Приложение

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    Popularity of investment of means in the share market steadily increases. Therefore, there is a demand of design of various financial products, leaning on objective and desires of the investor. Practical realization of construction complex опционных strategy in view of preferences of the investor is resulted

    Fabrication and examination of oxidation resistance of zinc coated copper and brass components by chemical deposition

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    n this work, the structure and the oxidation resistance of Zn deposited Cu and brass metallic components are examined. The deposition was accomplished with pack cementation chemical deposition. The examination of the samples was performed with electron microscopy and X-ray diffraction analysis. It was found that coatings on Cu substrate consist of two layers with different Zn concentrations, while coatings on brass were single layered with almost constant Zn concentration. The presence of distinct Zn—Cu phases was revealed in both cases. The subjection of the as coated samples together with the uncoated substrates in air at 400ºC showed that both Zn coated samples have enhanced resistivity in such atmospheres, as most of the coating remained mostly unoxidised, and the substrates were fully protected. On the contrary, the bare substrates appear to have undergone severe damage as brittle oxides were formed on their surface.Publicad

    Intra-Domain Adaptation for Robust Visual Guidance in Intratympanic Injections

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    Intratympanic steroid injections are commonly used for the treatment of ear diseases. During this treatment, an expert Ear, Nose & Throat (ENT) clinician delivers the drug by viewing through a large microscope that provides a close-up view of the anatomical landmarks on the middle ear. A steady hand and swift response to any patient movement are required to avoid improper placement of the needle. To assist the clinician during this treatment, a fluidic soft robot is proposed in \cite{lindenroth2021fluidic} that can steer inside a lumen for providing steady guidance for drug delivery. For robust visual guidance, stable anatomical landmarks (tympanic membrane, malleus, umbo) segmentation is required. In this work, we perform intra-domain adaptation to learn a generalized model that provides stable and consistent segmentation on unseen patients and phantom ear data

    Ultraviolet Fe II Emission in Fainter Quasars: Luminosity Dependences, and the Influence of Environments

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    We investigate the strength of ultraviolet Fe II emission in fainter quasars com- pared with brighter quasars for 1.0 :( z :( 1.8, using the SDSS (Sloan Digital Sky Survey) DR7QSO catalogue and spectra of Schneider et al., and the SFQS (SDSS Faint Quasar Survey) catalogue and spectra of Jiang et al. We quantify the strength of the UV Fe II emission using the W 2400 equivalent width of Weymann et al., which is defined between two rest-frame continuum windows at 2240–2255 and 2665–2695 ˚A. The main results are the following. (1) We find that for W 2400 2: 25 ˚A there is a universal (i.e. for quasars in general) strengthening of W 2400 with decreasing intrinsic luminosity, L3000. (2) In conjunction with previous work by Clowes et al., we find that there is a further, differential, strengthening of W 2400 with decreasing L3000 for those quasars that are members of Large Quasar Groups (LQGs). (3) We find that increasingly strong W 2400 tends to be associated with decreasing FWHM of the neighbouring Mg II λ2798 broad emission line. (4) We suggest that the dependence of W 2400 on L3000 arises from Lyα fluorescence. (5) We find that stronger W 2400 tends to be associated with smaller virial estimates from Shen et al. of the mass of the central black hole, by a factor ∼ 2 between the ultrastrong emitters and the weak. Stronger W 2400 emission would correspond to smaller black holes that are still growing. The differential effect for LQG members might then arise from preferentially younger quasars in the LQG environments

    Controlling the nuclear polarization in quantum dots using optical pulses with a modest bandwidth

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    We show that detuned optical pulse trains with a modest spectral width can polarize nuclear spins in InAs quantum dots. The pulse bandwidth is large enough to excite a coherent superposition of both electron spin eigenstates in these negatively charged dots but narrow enough to give partial spectral selectivity between the eigenstates. The coherent precession of electron spin states and periodic excitation focuses the nuclear spin distribution, producing a discrete set of precession modes. The spectral selectivity generates a net nuclear polarization, through a mechanism that relies on optical spin rotations rather than electron spin relaxation.Comment: 7 pages, 7 figure
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