Active and Passive Quantum Erasers for Neutral Kaons

Quantum marking and quantum erasure are discussed for the neutral kaon system. Contrary to other two-level systems, strangeness and lifetime of a neutral kaon state can be alternatively measured via an "active" or a "passive" procedure. This offers new quantum erasure possibilities. In particular, the operation of a quantum eraser in the "delayed choice" mode is clearly illustrated.Comment: 17 pages, LaTeX, 1 figure, references added, accepted by Phys. Rev.

Energy Savings via Harnessing Partial Packets in Body Area Networks

This work considers the incorporation, implications and potential energy savings of partial packet recovery schemes in Body Area Networks (BANs). Received packets which have not been fully corrected by the physical layer, called partial, are discarded by the vast majority of BAN protocols, as opposed to valid packets, which satisfy the error detection check and are propagated to higher layers. In typical networks using ARQ protocols, dropping partial packets results in retransmissions. However, because these packets contain useful information, partial packet recovery schemes have been proposed with demonstrated throughput and reliability benefits, targeting mostly wireless LANs. In order to quantify the potential energy benefits of harnessing partial packets in BANs, we use an experimental setup with four sensors mounted on a human body, transmitting information to a receiving node in a typical office environment. By precisely modeling the state transitions and energy consumption of sensors, we compare the efficiency of a baseline ARQ protocol against a scheme which leverages information in partial packets. Our results indicate that exploiting partial packets reduces on average the energy consumption of our sensors by 8--20%. The energy savings are pronounced in challenged channel conditions of high PER, where they can be up to 50%

Superparamagnetic iron oxide nanoparticles regulate smooth muscle cell phenotype

Superparamagnetic iron oxide nanoparticles are used for an increasing range of biomedical applications, from imaging to mechanical actuation of cells and tissue. The aim of this study was to investigate the loading of smooth muscle cells with superparamagnetic iron oxide nanoparticles and to explore what effect this has on the phenotype of the cells. Adherent human smooth muscle cells were loaded with ∼17 pg of unconjugated, negatively charged, 50 nm superparamagnetic iron oxide nanoparticles (SPION). Clusters of the internalized SPION particles were held in discrete cytoplasmic vesicles. Internalized SPION did not cause any change in cell morphology, proliferation, metabolic activity, or staining pattern of actin and calponin, two of the muscle contractile proteins involved in force generation. However, internalized SPION inhibited the increased gene expression of actin and calponin normally observed when cells are incubated under differentiation conditions. The observed change in the control of gene expression of muscle contractile apparatus by SPION has not previously been described. This finding could offer novel approaches for regulating the phenotype of smooth muscle cells and warrants further investigation. This article is protected by copyright. All rights reserved

Experimental study of the interplay of channel and network coding in low power sensor applications

In this paper, we evaluate the performance of random linear network coding (RLNC) in low data rate indoor sensor applications operating in the ISM frequency band. We also investigate the results of its synergy with forward error correction (FEC) codes at the PHY-layer in a joint channel-network coding (JCNC) scheme. RLNC is an emerging coding technique which can be used as a packet-level erasure code, usually implemented at the network layer, which increases data reliability against channel fading and severe interference, while FEC codes are mainly used for correction of random bit errors within a received packet. The hostile wireless environment that low power sensors usually operate in, with significant interference from nearby networks, motivates us to consider a joint coding scheme and examine the applicability of RLNC as an erasure code in such a coding structure. Our analysis and experiments are performed using a custom low power sensor node, which integrates on-chip a low-power 2.4 GHz transmitter and an accelerator implementing a multi-rate convolutional code and RLNC, in a typical office environment. According to measurement results, RLNC of code rate 4/8 can provide an effective SNR improvement of about 3.4 dB, outperforming a PHY-layer FEC code of the same code rate, at a PER of 10[superscript -2]. In addition, RLNC performs very well when used in conjunction with a PHY-layer FEC code as a JCNC scheme, offering an overall coding gain of 5.6 dB.Focus Center Research Program. Focus Center for Circuit & System Solutions. Semiconductor Research Corporation. Interconnect Focus Cente

Considerations on Super Poincare Algebras and their Extensions to Simple Superalgebras

We consider simple superalgebras which are a supersymmetric extension of \fspin(s,t) in the cases where the number of odd generators does not exceed 64. All of them contain a super Poincar\'e algebra as a contraction and another as a subalgebra. Because of the contraction property, some of these algebras can be interpreted as de Sitter or anti de Sitter superalgebras. However, the number of odd generators present in the contraction is not always minimal due to the different splitting properties of the spinor representations under a subalgebra. We consider the general case, with arbitrary dimension and signature, and examine in detail particular examples with physical implications in dimensions $d=10$ and $d=4$.Comment: 16 pages, AMS-LaTeX. Version to appear in the Reviews in Mathematical Physic

Evolution of kinklike fluctuations associated with ion pickup within reconnection outflows in the Earth's magnetotail

Magnetic reconnection (MR) in Earth's magnetotail is usually followed by a systemwide redistribution of explosively released kinetic and thermal energy. Recently, multispacecraft observations from the THEMIS mission were used to study localized explosions associated with MR in the magnetotail so as to understand subsequent Earthward propagation of MR outbursts during substorms. Here we investigate plasma and magnetic field fluctuations/structures associated with MR exhaust and ion-ion kink mode instability during a well documented MR event. Generation, evolution and fading of kinklike oscillations are followed over a distance of 70 000 km from the reconnection site in the midmagnetotail to the more dipolar region near the Earth. We have found that the kink oscillations driven by different ion populations within the outflow region can be at least 25 000 km from the reconnection site.Comment: 11 pages, 4 figure

Direct test of time-reversal symmetry in the entangled neutral kaon system at a ϕ\phi-factory

We present a novel method to perform a direct T (time reversal) symmetry test in the neutral kaon system, independent of any CP and/or CPT symmetry tests. This is based on the comparison of suitable transition probabilities, where the required interchange of in out states for a given process is obtained exploiting the Einstein-Podolsky-Rosen correlations of neutral kaon pairs produced at a $\phi$-factory. In the time distribution between the two decays, we compare a reference transition like the one defined by the time ordered decays $(\ell^-,\pi\pi)$ with the T -conjugated one defined by $(3\pi^0, \ell^+)$. With the use of this and other T conjugated comparisons, the KLOE-2 experiment at DA$\Phi$NE could make a significant test