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BackgroundWe used structural equation modeling to evaluate the quality of life (QOL) for patients with Marfan syndrome (MFS). The goal was to provide guidelines to facilitate the development of interventions and strategies to improve the QOL for patients with MFS.MethodsThe participants fulfilled the Ghent 2 criteria for MFS and they comprised patients who visited the cardiology outpatient department of a tertiary hospital in Seoul, Korea, between August 17, 2013 and April 17, 2014. Demographic, social support, disease-related factors, biobehavioral factors, and QOL data were collected in one-on-one interviews.ResultsThe final analyses included 218 patients. Anxious and depressed patients comprised 63.8 and 71.5 % of the sample, respectively. For the hypothetical model, the goodness-of-fit index = 0.91, normal fit index = 0.93, and comparative fit index = 0.90. The outcome was suitable for the recommended level, so the hypothetical model appeared to fit the data. In patients with MFS, the QOL was affected significantly by social support, disease-related factors, and biobehavioral factors. These variables explained 72.4 % of the QOL in patients with MFS. Biobehavioral factors had the strongest and most direct effects on QOL.ConclusionTo improve QOL in patients with MFS, comprehensive interventions are necessary to assess and manage biobehavioral factors, social support, and disease-related factors.

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CT and MRI facilitate definite diagnosis of unroofed coronary sinus syndrome.

A capacity-achieving scheme based on polar codes is proposed for reliable communication over multi-channels which can be directly applied to bit-interleaved coded modulation schemes. We start by reviewing the ground-breaking work of polar codes and then discuss our proposed scheme. Instead of encoding separately across the individual underlying channels, which requires multiple encoders and decoders, we take advantage of the recursive structure of polar codes to construct a unified scheme with a single encoder and decoder that can be used over the multi-channels. We prove that the scheme achieves the capacity over this multi-channel. Numerical analysis and simulation results for BICM channels at finite block lengths shows a considerable improvement in the probability of error comparing to a conventional separated scheme.

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A polar coding scheme is proposed for reliable communication over channels with bit interleaved coded modulation (BICM). In an ideal information theoretic model, BICM schemes are modeled as a set of multiple binary input channels that experience different reliabilities. This model is referred to as multichannel. The conventional scheme for encoding information over multi-channels is to encode separately across the individual constituent channels which requires multiple encoders and decoders. As opposed to the conventional scheme, we take advantage of the recursive structure of polar codes in order to construct a unified compound polar code. The proposed scheme has a single encoder and decoder and can be used over multi-channels, in particular over channels with BICM. We prove that the scheme achieves the multi-channel capacity with the same error decay rate as in Arıkan's polar codes. Furthermore, due to more levels of channel polarization, we obtain a better finite block length performance compared to the separated polarization scheme. This is confirmed through various simulations over the binary erasure channel, as well as with transmissions over AWGN and fast fading channels with BICM and different modulation orders. Index Terms-Bit-interleaved coded modulation, compound polar code, channel polarization, multi-channels, capacity0018-9545 (c)

Abstract-A scheme for concatenating the recently invented polar codes with non-binary MDS codes, as Reed-Solomon codes, is considered. By concatenating binary polar codes with interleaved Reed-Solomon codes, we prove that the proposed concatenation scheme captures the capacity-achieving property of polar codes, while having a significantly better error-decay rate. We show that for any > 0, and total frame length N , the parameters of the scheme can be set such that the frame error probability is less than 2, while the scheme is still capacity achieving. This improves upon 2 −N 0.5− , the frame error probability of Arikan's polar codes. The proposed concatenated polar codes and Arikan's polar codes are also compared for transmission over channels with erasure bursts. We provide a sufficient condition on the length of erasure burst which guarantees failure of the polar decoder. On the other hand, it is shown that the parameters of the concatenated polar code can be set in such a way that the capacity-achieving properties of polar codes are preserved. We also propose decoding algorithms for concatenated polar codes, which significantly improve the error-rate performance at finite block lengths while preserving the low decoding complexity.