Can Punctured Rate-1/2 Turbo Codes Achieve a Lower Error Floor than their Rate-1/3 Parent Codes?

In this paper we concentrate on rate-1/3 systematic parallel concatenated convolutional codes and their rate-1/2 punctured child codes. Assuming maximum-likelihood decoding over an additive white Gaussian channel, we demonstrate that a rate-1/2 non-systematic child code can exhibit a lower error floor than that of its rate-1/3 parent code, if a particular condition is met. However, assuming iterative decoding, convergence of the non-systematic code towards low bit-error rates is problematic. To alleviate this problem, we propose rate-1/2 partially-systematic codes that can still achieve a lower error floor than that of their rate-1/3 parent codes. Results obtained from extrinsic information transfer charts and simulations support our conclusion.Comment: 5 pages, 7 figures, Proceedings of the 2006 IEEE Information Theory Workshop, Chengdu, China, October 22-26, 200

On the analogy between vehicle and vehicle-like cavities with reverberation chambers

Deploying wireless systems in vehicles is an area of current interest. Often, it is implicitly assumed that the electromagnetic environment in vehicle cavities is analogous to that in reverberation chambers, it is therefore important to assess to what extent this analogy is valid. Specifically, the cavity time constant, electromagnetic isolation and electric field uniformity are investigated for typical vehicle and vehicle-like cavities. It is found that the time constant is a global property of the cavity (i.e., it is the same for all links). This is important, as it means that the root mean square delay spread for any link is also a property of the cavity, and thus so is the coherence bandwidth. These properties could be exploited by wireless sytems deployed in vehicles. It is also found that the field distribution is not homogeneous (and is therefore not uniform), but can be isotropic. For situations where the field distribution is isotropic, the spatial coherence is well defined, and therefore Multiple-Input-Multiple-Output antenna arrays can be used to improve performance of wireless systems. For situations where the field distribution is not isotropic, the angular spread is not uniform, and therefore beam-forming can be used to improve performance of wireless systems.This is the author's accepted manuscript and will be under embargo until publication. The final version is available from IEEE at http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=692843

Characterizing the spectral properties and time variation of the in-vehicle wireless communication channel

To deploy effective communication systems in vehicle cavities, it is critical to understand the time variation of the in-vehicle channel. Initially rapid channel variation is addressed, which is characterised in the frequency domain as a Doppler spread. It is then shown that for typical Doppler spreads, the in-vehicle channel is underspread, and therefore the information capacity approaches the capacity achieved with perfect receiver channel state information in the infinite bandwidth limit. Measurements are performed for a number of channel variation scenarios (absorptive motion, reflective motion, one antenna moving, both antennas moving), at a number of carrier frequencies and for a number of cavity loading scenarios. It is found that the Doppler spread increases with carrier frequency, however the type of channel variation and loading appear to have little effect. Channel variation over a longer time period is also measured, to characterise the slower channel variation. Channel variation is a function of the cavity occupant motion, which is difficult to model theoretically, therefore an empirical model for the slow channel variation is proposed, which leads to an improved estimate of the channel state.This work is supported by the U.K. Engineering and Physical Sciences Research Council (EPSRC) and National Physical Laboratory (NPL) under an EPSRC-NPL Industrial CASE studentship programme on the subject of intra-Vehicular Wireless Sensor Networks. The work of T. H. Loh was supported by the 2009 - 2012 Physical Program and 2012 - 2015 Electromagnetic Metrology Program of the National Measurement Office, an Executive Agency of the U.K. Department for Business, Innovation and Skills, under Projects 113860 and EMT13020, respectively.This is the author accepted manuscript. The final version can be found on the publisher's website at: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=682581

Proteomic analysis of nipple aspirate fluid to detect biologic markers of breast cancer.

The early detection of breast cancer is the best means to minimise disease-related mortality. Current screening techniques have limited sensitivity and specificity. Breast nipple aspirate fluid can be obtained noninvasively and contains proteins secreted from ductal and lobular epithelia. Nipple aspirate fluid proteins are breast specific and generally more concentrated than corresponding blood levels. Proteomic analysis of 1 microl of diluted nipple aspirate fluid over a 5-40 kDa range from 20 subjects with breast cancer and 13 with nondiseased breasts identified five differentially expressed proteins. The most sensitive and specific proteins were 6500 and 15 940 Da, found in 75-84% of samples from women with cancer but in only 0-9% of samples from normal women. These findings suggest that (1) differential expression of nipple aspirate fluid proteins exists between women with normal and diseased breasts, and (2) analysis of these proteins may predict the presence of breast cancer

ISA semantics for ARMV8-A, RISC-V, and ChERI-MIPs

Architecture specifications notionally define the fundamental interface between hardware and software: the envelope of allowed behaviour for processor implementations, and the basic assumptions for software development and verification. But in practice, they are typically prose and pseudocode documents, not rigorous or executable artifacts, leaving software and verification on shaky ground. In this paper, we present rigorous semantic models for the sequential behaviour of large parts of the mainstream ARMv8-A, RISC-V, and MIPS architectures, and the research CHERI-MIPS architecture, that are complete enough to boot operating systems, variously Linux, FreeBSD, or seL4. Our ARMv8-A models are automatically translated from authoritative ARM-internal definitions, and (in one variant) tested against the ARM Architecture Validation Suite. We do this using a custom language for ISA semantics, Sail, with a lightweight dependent type system, that supports automatic generation of emulator code in C and OCaml, and automatic generation of proof-assistant definitions for Isabelle, HOL4, and (currently only for MIPS) Coq. We use the former for validation, and to assess specification coverage. To demonstrate the usability of the latter, we prove (in Isabelle) correctness of a purely functional characterisation of ARMv8-A address translation. We moreover integrate the RISC-V model into the RMEM tool for (user-mode) relaxed-memory concurrency exploration. We prove (on paper) the soundness of the core Sail type system. We thereby take a big step towards making the architectural abstraction actually well-defined, establishing foundations for verification and reasoning.</jats:p

Biomagnetic of Apatite-Coated Cobalt Ferrite: A Core–Shell Particle for Protein Adsorption and pH-Controlled Release

Magnetic nanoparticle composite with a cobalt ferrite (CoFe2O4, (CF)) core and an apatite (Ap) coating was synthesized using a biomineralization process in which a modified simulated body fluid (1.5SBF) solution is the source of the calcium phosphate for the apatite formation. The core–shell structure formed after the citric acid–stabilized cobalt ferrite (CFCA) particles were incubated in the 1.5 SBF solution for 1 week. The mean particle size of CFCA-Ap is about 750 nm. A saturation magnetization of 15.56 emug-1 and a coercivity of 1808.5 Oe were observed for the CFCA-Ap obtained. Bovine serum albumin (BSA) was used as the model protein to study the adsorption and release of the proteins by the CFCA-Ap particles. The protein adsorption by the CFCA-Ap particles followed a more typical Freundlich than Langmuir adsorption isotherm. The BSA release as a function of time became less rapid as the CFCA-Ap particles were immersed in higher pH solution, thus indicating that the BSA release is dependent on the local pH

Social Pedagogy: Developing and Maintaining Multi-Disciplinary Relationships in Residential Child Care

The task of building and maintaining effective multi-disciplinary relationships is a constant challenge for the residential child care sector in Scotland. The absence of effective multi-disciplinary collaboration has been cited regularly as a contributing factor to instances of poor and problematic practice. Social pedagogy has much to offer in terms of enabling the residential child care sector to address some of these issues and assist with the task of establishing effective multi-disciplinary relationships. This article will explore how this can be achieved in practice, drawing on research based on multi-disciplinary social pedagogy training delivered in Scotland. The evidence demonstrates that social pedagogy can begin to break down the very real barriers that often prevent residential child care practitioners from developing and maintaining multi-disciplinary relationships. It can assist with the task of developing a shared language and understanding; the creation of a clear focus on the developmental needs of children and young people; and a more nuanced approach to dealing with issues of risk. The messages from this article will hold relevance for the professions of residential child care, health and education and be applicable to practitioners throughout Europe and beyond

Resolving the CO Snow Line in the Disk around HD 163296

We report Submillimeter Array (SMA) observations of CO (J=2--1, 3--2 and 6--5) and its isotopologues (13CO J=2--1, C18O J=2--1 and C17O J=3--2) in the disk around the Herbig Ae star HD 163296 at ~2" (250 AU) resolution, and interpret these data in the framework of a model that constrains the radial and vertical location of the line emission regions. First, we develop a physically self-consistent accretion disk model with an exponentially tapered edge that matches the spectral energy distribution and spatially resolved millimeter dust continuum emission. Then, we refine the vertical structure of the model using wide range of excitation conditions sampled by the CO lines, in particular the rarely observed J=6--5 transition. By fitting 13CO data in this structure, we further constrain the vertical distribution of CO to lie between a lower boundary below which CO freezes out onto dust grains (T ~ 19 K) and an upper boundary above which CO can be photodissociated (the hydrogen column density from the disk surface is ~ 10^{21} cm-2). The freeze-out at 19 K leads to a significant drop in the gas-phase CO column density beyond a radius of ~155 AU, a "CO snow line" that we directly resolve. By fitting the abundances of all CO isotopologues, we derive isotopic ratios of 12C/13C, 16O/18O and 18O/17O that are consistent with quiescent interstellar gas-phase values. This detailed model of the HD 163296 disk demonstrates the potential of a staged, parametric technique for constructing unified gas and dust structure models and constraining the distribution of molecular abundances using resolved multi-transition, multi-isotope observations.Comment: 40 pages, 13 figures, accepted for publication in Ap

Haptoglobin phenotype is not a predictor of recurrence free survival in high-risk primary breast cancer patients

Contains fulltext : 70104tjan-heijnen.pdf (publisher's version ) (Open Access)BACKGROUND: Better breast cancer prognostication may improve selection of patients for adjuvant therapy. We conducted a retrospective follow-up study in which we investigated sera of high-risk primary breast cancer patients, to search for proteins predictive of recurrence free survival. METHODS: Two sample sets of high-risk primary breast cancer patients participating in a randomised national trial investigating the effectiveness of high-dose chemotherapy were analysed. Sera in set I (n = 63) were analysed by surface enhanced laser desorption ionisation time-of-flight mass spectrometry (SELDI-TOF MS) for biomarker finding. Initial results were validated by analysis of sample set II (n = 371), using one-dimensional gel-electrophoresis. RESULTS: In sample set I, the expression of a peak at mass-to-charge ratio 9198 (relative intensity 20), identified as haptoglobin (Hp) alpha-1 chain, was strongly associated with recurrence free survival (global Log-rank test; p = 0.0014). Haptoglobin is present in three distinct phenotypes (Hp 1-1, Hp 2-1, and Hp 2-2), of which only individuals with phenotype Hp 1-1 or Hp 2-1 express the haptoglobin alpha-1 chain. As the expression of the haptoglobin alpha-1 chain, determined by SELDI-TOF MS, corresponds to the phenotype, initial results were validated by haptoglobin phenotyping of the independent sample set II by native one-dimensional gel-electrophoresis. With the Hp 1-1 phenotype as the reference category, the univariate hazard ratio for recurrence was 0.87 (95% CI: 0.56 - 1.34, p = 0.5221) and 1.03 (95% CI: 0.65 - 1.64, p = 0.8966) for the Hp 2-1 and Hp 2-2 phenotypes, respectively, in sample set II. CONCLUSION: In contrast to our initial results, the haptoglobin phenotype was not identified as a predictor of recurrence free survival in high-risk primary breast cancer in our validation set. Our initial observation in the discovery set was probably the result of a type I error (i.e. false positive). This study illustrates the importance of validation in obtaining the true clinical applicability of a potential biomarker