1,448 research outputs found

    Secrecy Results for Compound Wiretap Channels

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    We derive a lower bound on the secrecy capacity of the compound wiretap channel with channel state information at the transmitter which matches the general upper bound on the secrecy capacity of general compound wiretap channels given by Liang et al. and thus establishing a full coding theorem in this case. We achieve this with a stronger secrecy criterion and the maximum error probability criterion, and with a decoder that is robust against the effect of randomisation in the encoding. This relieves us from the need of decoding the randomisation parameter which is in general not possible within this model. Moreover we prove a lower bound on the secrecy capacity of the compound wiretap channel without channel state information and derive a multi-letter expression for the capacity in this communication scenario.Comment: 25 pages, 1 figure. Accepted for publication in the journal "Problems of Information Transmission". Some of the results were presented at the ITW 2011 Paraty [arXiv:1103.0135] and published in the conference paper available at the IEEE Xplor

    Information-Theoretic Secret-Key Agreement: The Asymptotically Tight Relation Between the Secret-Key Rate and the Channel Quality Ratio

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    Information-theoretically secure secret-key agreement between two parties Alice and Bob is a well-studied problem that is provably impossible in a plain model with public (authenticated) communication, but is known to be possible in a model where the parties also have access to some correlated randomness. One particular type of such correlated randomness is the so-called satellite setting, where a source of uniform random bits (e.g., sent by a satellite) is received by the parties and the adversary Eve over inherently noisy channels. The antenna size determines the error probability, and the antenna is the adversary\u27s limiting resource much as computing power is the limiting resource in traditional complexity-based security. The natural assumption about the adversary is that her antenna is at most QQ times larger than both Alice\u27s and Bob\u27s antenna, where, to be realistic, QQ can be very large. The goal of this paper is to characterize the secret-key rate per transmitted bit in terms of QQ. Traditional results in this so-called satellite setting are phrased in terms of the error probabilities ϵA\epsilon_A, ϵB\epsilon_B, and ϵE\epsilon_E, of the binary symmetric channels through which the parties receive the bits and, quite surprisingly, the secret-key rate has been shown to be strictly positive unless Eve\u27s channel is perfect (ϵE=0\epsilon_E=0) or either Alice\u27s or Bob\u27s channel output is independent of the transmitted bit (i.e., ϵA=0.5\epsilon_A=0.5 or ϵB=0.5\epsilon_B=0.5). However, the best proven lower bound, if interpreted in terms of the channel quality ratio QQ, is only exponentially small in QQ. The main result of this paper is that the secret-key rate decreases asymptotically only like 1/Q21/Q^2 if the per-bit signal energy, affecting the quality of all channels, is treated as a system parameter that can be optimized. Moreover, this bound is tight if Alice and Bob have the same antenna sizes. Motivated by considering a fixed sending signal power, in which case the per-bit energy is inversely proportional to the bit-rate, we also propose a definition of the secret-key rate per second (rather than per transmitted bit) and prove that it decreases asymptotically only like 1/Q1/Q

    Outcomes by Cardiac Stage in Patients With Newly Diagnosed AL Amyloidosis: Phase 3 ANDROMEDA Trial

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    BACKGROUND: Patients with amyloid light chain amyloidosis and severe cardiac dysfunction have a poor prognosis. Treatment options that induce rapid and deep hematologic and organ responses, irrespective of cardiac involvement, are needed. OBJECTIVES: The aim of this study was to evaluate the impact of baseline cardiac stage on efficacy and safety outcomes in the phase 3 ANDROMEDA trial. METHODS: Rates of overall complete hematologic response and cardiac and renal response at 6 months and median major organ deterioration–progression-free survival and major organ deterioration–event-free survival were compared across cardiac stages (I, II, or IIIA) and treatments (daratumumab, bortezomib, cyclophosphamide, and dexamethasone [D-VCd] or bortezomib, cyclophosphamide, and dexamethasone [VCd]). Rates of adverse events (AEs) were summarized for patients with and without baseline cardiac involvement and by cardiac stage. RESULTS: Median follow-up duration was 15.7 months. The proportions of stage I, II, and IIIA patients were 23.2%, 40.2%, and 36.6%. Across cardiac stages, hematologic and organ response rates were higher and major organ deterioration–progression-free survival and major organ deterioration–event-free survival were longer with D-VCd than VCd. AE rates were similar between treatments and by cardiac stage; serious AE rates were higher in patients with cardiac involvement and increased with increasing cardiac stage. The incidence of cardiac events was numerically greater with D-VCd vs VCd, but the rate of grade 3 or 4 events was similar. The exposure-adjusted incidence rate for cardiac events was lower with D-VCd than VCd (median exposure 13.4 and 5.3 months, respectively). CONCLUSIONS: These findings demonstrate the efficacy of D-VCd over VCd in patients with newly diagnosed amyloid light chain amyloidosis across cardiac stages, thus supporting its use in patients with cardiac involvement. (NCT03201965

    Valley splitting of single-electron Si MOS quantum dots

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    Silicon-based metal-oxide-semiconductor quantum dots are prominent candidates for high-fidelity, manufacturable qubits. Due to silicon's band structure, additional low-energy states persist in these devices, presenting both challenges and opportunities. Although the physics governing these valley states has been the subject of intense study, quantitative agreement between experiment and theory remains elusive. Here, we present data from an experiment probing the valley states of quantum dot devices and develop a theory that is in quantitative agreement with both this and a recently reported experiment. Through sampling millions of realistic cases of interface roughness, our method provides evidence that the valley physics between the two samples is essentially the same.J.K.G. gratefully acknowledges support from the Sandia National Laboratories Truman Fellowship Program, which is funded by the Laboratory Directed Research and Development (LDRD) program. This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. C.H.Y. and A.S.D. acknowledge support from the Australian Research Council (CE11E0001017), the U.S. Army Research Office (W911NF-13-1-0024) and the NSW Node of the Australian National Fabrication Facility. A.R. acknowledges support from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement No. 654712 (SINHOPSI)

    Intravenous leiomyomatosis of the uterus with extension to the right heart

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    A 42-year-old woman admitted with debilitation and engorgement both lower extremities. Transthoracic two-dimensional echocardiography, abdominal ultrasound and computerized tomography revealed a lobulated pelvic mass, a mass within right internal iliac vein, both common iliac vein, as well as the inferior vena cava, extending into the right atrium. In addition, echocardiography and abdominal ultrasound showed the tumor of right atrium and inferior vena cave has no stalk and has well-demarcated borders with the wall of right atrium and inferior vena cave. Hence, the presumptive diagnosis of IVL was made by echocardiography and abdominal ultrasound and the presumptive diagnosis of sarcoma with invasion in right internal iliac vein, both common iliac vein, the inferior vena cava, as well as the right atrium was made by multi-detector-row computerized tomography. The patient underwent a one-stage combined multidisciplinary thoraco-abdominal operation under general anaesthetic. Subsequently the pathologic report confirmed IVL

    Stable Modality-Specific Activity Flows As Reflected by the Neuroenergetic Approach to the fMRI Weighted Maps

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    This article uses the ideas of neuroenergetic and neural field theories to detect stimulation-driven energy flows in the brain during face and auditory word processing. In this analysis, energy flows are thought to create the stable gradients of the fMRI weighted summary images. The sources, from which activity spreads in the brain during face processing, were detected in the occipital cortex. The following direction of energy flows in the frontal cortex was described: the right inferior frontal = >the left inferior frontal = >the triangular part of the left inferior frontal cortex = >the left operculum. In the left operculum, a localized circuit was described. For auditory word processing, the sources of activity flows were detected bilaterally in the middle superior temporal regions, they were also detected in the left posterior superior temporal cortex. Thus, neuroenergetic assumptions may give a novel perspective for the analysis of neuroimaging data

    Essential function for ErbB3 in breast cancer proliferation

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    The overexpression of the ErbB family of tyrosine kinase receptors is thought to be important in the development of many breast tumours. To date, most attention has focused on the ErbB2 receptor. Now, in a recent report, it has been shown that ErbB3 is a critical partner for the transforming activity of ErbB2 in breast cancer cells. Importantly, the proliferative signals from this transforming complex appear to act via the PI-3 kinase pathway

    SPARC functions as an inhibitor of adipogenesis

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    Adipogenesis, a key step in the pathogenesis of obesity, involves extensive ECM remodeling, changes in cell-ECM interactions, and cytoskeletal rearrangement. Matricellular proteins regulate cell-cell and cell-ECM interactions. Evidence in vivo and in vitro indicates that the prototypic matricellular protein, SPARC, inhibits adipogenesis and promotes osteoblastogenesis. Herein we discuss mechanisms underlying the inhibitory effect of SPARC on adipogenesis. SPARC enhances the Wnt/β-catenin signaling pathway and regulates the expression and posttranslational modification of collagen. SPARC might drive preadipocytes away from the status of growth arrest and therefore prevent terminal differentiation. SPARC could also decrease WAT deposition through its negative effects on angiogenesis. Therefore, several stages of white adipose tissue accumulation are sensitive to the inhibitory effects of SPARC

    Identification of a Novel Class of Farnesylation Targets by Structure-Based Modeling of Binding Specificity

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    Farnesylation is an important post-translational modification catalyzed by farnesyltransferase (FTase). Until recently it was believed that a C-terminal CaaX motif is required for farnesylation, but recent experiments have revealed larger substrate diversity. In this study, we propose a general structural modeling scheme to account for peptide binding specificity and recapitulate the experimentally derived selectivity profile of FTase in vitro. In addition to highly accurate recovery of known FTase targets, we also identify a range of novel potential targets in the human genome, including a new substrate class with an acidic C-terminal residue (CxxD/E). In vitro experiments verified farnesylation of 26/29 tested peptides, including both novel human targets, as well as peptides predicted to tightly bind FTase. This study extends the putative range of biological farnesylation substrates. Moreover, it suggests that the ability of a peptide to bind FTase is a main determinant for the farnesylation reaction. Finally, simple adaptation of our approach can contribute to more accurate and complete elucidation of peptide-mediated interactions and modifications in the cell
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