22,686 research outputs found

    Nuclear fusion as a probe for octupole deformation in 224^{224}Ra

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    Background\textit{Background}: Nuclear fusion has been shown to be a perfect probe to study the different nuclear shapes. However, the possibility of testing octupole deformation of a nucleus with this tool has not been fully explored yet. The presence of a stactic octupole deformation in nuclei will enhanced a possible permanent electric dipole moment, leading to a possible demonstration of parity violation. Purpose\textit{Purpose}: To check whether static octupole deformation or octupole vibration in fusion give qualitatively different results so that both situations can be experimentally disentangled. Method\textit{Method}: Fusion cross sections are computed in the Coupled-Channels formalism making use of the Ingoing-Wave Boundary Conditions (IWBC) for the systems 16^{16}O+144^{144}Ba and 16^{16}O+224^{224}Ra. Results\textit{Results}: Barrier distributions of the two considered schemes show different patterns. For the 224^{224}Ra case, the octupole deformation parameter is large enough to create a sizeable difference. Conclusions\textit{Conclusions}: The measurement of barrier distributions can be an excellent probe to clarify the presence of octupole deformation.Comment: Important changes from previous version, 6 pages, 5 figures, 2 tables, submitted to Phys. Rev.

    Inferring Room Semantics Using Acoustic Monitoring

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    Having knowledge of the environmental context of the user i.e. the knowledge of the users' indoor location and the semantics of their environment, can facilitate the development of many of location-aware applications. In this paper, we propose an acoustic monitoring technique that infers semantic knowledge about an indoor space \emph{over time,} using audio recordings from it. Our technique uses the impulse response of these spaces as well as the ambient sounds produced in them in order to determine a semantic label for them. As we process more recordings, we update our \emph{confidence} in the assigned label. We evaluate our technique on a dataset of single-speaker human speech recordings obtained in different types of rooms at three university buildings. In our evaluation, the confidence\emph{ }for the true label generally outstripped the confidence for all other labels and in some cases converged to 100\% with less than 30 samples.Comment: 2017 IEEE International Workshop on Machine Learning for Signal Processing, Sept.\ 25--28, 2017, Tokyo, Japa

    Current Status of Defensins and Their Role in Innate and Adaptive Immunity

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    Naturally occurring antimicrobial cationic polypeptides play a major role in innate and adaptive immunity. These polypeptides are found to be either linear and unstructured or structured through disulfide bonds. Among the structured antimicrobial polypeptides, defensins comprise a family of cysteine-rich cationic polypeptides that contribute significantly to host defense against the invasion of microorganisms in animals, humans, insects and plants. Their wide-spread occurrence in various tissues of these diverse organisms, and their importance in innate and adaptive immunity have led to their identification, isolation and characterization. A large volume of literature is available on defensins’ occurrence, structural characterization, gene expression and regulation under normal and pathological conditions. Much has also been published regarding their antimicrobial, antiviral and chemoattractive properties, and their molecular and cellular interactions. In this review, we describe the current status of our knowledge of defensins with respect to their molecular, cellular and structural biology, their role in host defense, future research paradigms and the possibility of their utilization as a new class of non-toxic antimicrobial agents and immuno-modulators

    Steady State Analysis and Heavy Traffic Limits for Regulated Markov Chains.

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    Consider a continuous time finite state irreducible Markov chain whose jump transitions are partitioned into one group that is regulated and the other group that is not. The regulated transitions are only allowed to occur if there is a token available. We collect the tokens in a buer and allow a regulated transition to occur simultaneously with the removal of a token from the buffer. New tokens are added to the buer at a constant Poisson rate but the regulated transitions will be blocked if they occur too quickly. We will apply matrix analysis to the joint distribution for the state of the Markov chain and the number of tokens in the buffer. We will give a simple stability condition for the joint process and show that its steady state distribution will have a matrix geometric distribution. Moreover, we obtain from our analysis a heavy traffic limit for this joint steady state distribution which has a product form structure. This Markov chain model and steady state analysis generalizes the work of many earlier papers on specific queueing systems such as Konheim and Reiser or Latouche and Neuts, but most significantly the work of Kogan and Puhalskii.Markov Chains, Matrix-Geometric Solution, Heavy-Traffic Limits, Product Form Solution, Tensor and Kronecker Products.

    Effect of InAlAs window layer on efficiency of indium phosphide solar cells

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    Indium phosphide (InP) solar cell efficiencies are limited by surface recombination. The effect of a wide bandgap, lattice-matched indium aluminum arsenide (In(0.52)Al(0.48)As) window layer on the performance of InP solar cells was investigated by using the numerical code PC-1D. The p(+)n InP solar cell performance improved significantly with the use of the window layer. No improvement was seen for the n(+)p InP cells. The cell results were explained by the band diagram of the heterostructure and the conduction band energy discontinuity. The calculated current voltage and internal quantum efficiency results clearly demonstrated that In(0.52)Al(0.48)As is a very promising candidate for a window layer material for p(+)n InP solar cells

    Large Margin Multiclass Gaussian Classification with Differential Privacy

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    As increasing amounts of sensitive personal information is aggregated into data repositories, it has become important to develop mechanisms for processing the data without revealing information about individual data instances. The differential privacy model provides a framework for the development and theoretical analysis of such mechanisms. In this paper, we propose an algorithm for learning a discriminatively trained multi-class Gaussian classifier that satisfies differential privacy using a large margin loss function with a perturbed regularization term. We present a theoretical upper bound on the excess risk of the classifier introduced by the perturbation.Comment: 14 page

    Asymptotic Performance of Linear Receivers in MIMO Fading Channels

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    Linear receivers are an attractive low-complexity alternative to optimal processing for multi-antenna MIMO communications. In this paper we characterize the information-theoretic performance of MIMO linear receivers in two different asymptotic regimes. For fixed number of antennas, we investigate the limit of error probability in the high-SNR regime in terms of the Diversity-Multiplexing Tradeoff (DMT). Following this, we characterize the error probability for fixed SNR in the regime of large (but finite) number of antennas. As far as the DMT is concerned, we report a negative result: we show that both linear Zero-Forcing (ZF) and linear Minimum Mean-Square Error (MMSE) receivers achieve the same DMT, which is largely suboptimal even in the case where outer coding and decoding is performed across the antennas. We also provide an approximate quantitative analysis of the markedly different behavior of the MMSE and ZF receivers at finite rate and non-asymptotic SNR, and show that while the ZF receiver achieves poor diversity at any finite rate, the MMSE receiver error curve slope flattens out progressively, as the coding rate increases. When SNR is fixed and the number of antennas becomes large, we show that the mutual information at the output of a MMSE or ZF linear receiver has fluctuations that converge in distribution to a Gaussian random variable, whose mean and variance can be characterized in closed form. This analysis extends to the linear receiver case a well-known result previously obtained for the optimal receiver. Simulations reveal that the asymptotic analysis captures accurately the outage behavior of systems even with a moderate number of antennas.Comment: 48 pages, Submitted to IEEE Transactions on Information Theor

    Novel Molecules for Intra-Oral Delivery of Antimicrobials to Prevent and Treat Oral Infectious Diseases

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    New molecules were designed for efficient intra-oral delivery of antimicrobials to prevent and treat oral infection. The salivary statherin fragment, which has high affinity for the tooth enamel, was used as a carrier peptide. This was linked through the side chain of the N-terminal residue to the C-terminus of a defensin-like 12-residue peptide to generate two bifunctional hybrid molecules, one with an ester linkage and the other with an anhydride bond between the carrier and the antimicrobial components. They were examined for their affinity to a HAP (hydroxyapatite) surface. The extent of the antimicrobial release in human whole saliva was determined using 13C-NMR spectroscopy. The candidacidal activity of the molecules was determined as a function of the antimicrobial release from the carrier peptide in human saliva. The hybrid-adsorbed HAP surface was examined against Candida albicans and Aggregatibacter actinomycetemcomitans using the fluorescence technique. The bifunctional molecules were tested on human erythrocytes, GECs (gingival epithelial cells) and GFCs (gingival fibroblast cells) for cytotoxicity. They were found to possess high affinity for the HAP mineral. In human whole saliva, a sustained antimicrobial release over a period of more than 40–60 h, and candidacidal activity consistent with the extent of hybrid dissociation were observed. Moreover, the bifunctional peptide-bound HAP surface was found to exhibit antimicrobial activity when suspended in clarified human saliva. The hybrid peptides did not show any toxic influence on human erythrocytes, GECs and GFCs. These novel hybrids could be safely used to deliver therapeutic agents intra-orally for the treatment and prevention of oral infectious diseases
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