Evaluation and implementation of cyclic permutation coding for power line communications

Abstract: Noise and attenuation, in the form of frequency disturbance, impulsive noise, additive white Gaussian noise (AWGN) and frequency selective fading, are the major setbacks in power line communications (PLC). In order to effectively combat this challenge, we thus report the development and implementation of a specially coded M-ary differential phase shift keying modulation scheme on narrowband PLC channel. The coding aspect involves the concatenation of conventional Reed Solomon (RS) code with cyclic permutation coding (CPC), resulting in what is termed RS-CPC scheme. The CPC employed in this work maps the output bits of a binary RS code onto non-binary CPC symbols, in a cyclic manner, with a view to improving the distance between two different sets of mapped symbols. For implementation over 230 V AC power line, software defined radio hardware, called the universal software radio peripherals (USRPs), were used, together with narrowband coupling circuits, to couple the signal to and receive it from the power line. Both by simulation and implementation, our scheme outperforms the conventional Reed Solomon-convolutional coding (RS-CC) specified in the G3-PLC standard. An added advantage is that our scheme is easier to implement

Pertinent Dirac structure for QCD sum rules of meson-baryon coupling constants

Using general baryon interpolating fields $J_B$ for $B= N, \Xi, \Sigma,$ without derivative, we study QCD sum rules for meson-baryon couplings and their dependence on Dirac structures for the two-point correlation function with a meson i\int d^4x e^{iqx} \bra 0|{\rm T}[J_B(x)\bar{J}_B(0)] |{\cal M}(p)\ket. Three distinct Dirac structures are compared: $i\gamma_5$, i\gamma_5\fslash{p}, and $\gamma_5\sigma_{\mu\nu}q^\mu p^\nu$ structures. From the dependence of the OPE on general baryon interpolating fields, we propose criteria for choosing an appropriate Dirac structure for the coupling sum rules. The $\gamma_5\sigma_{\mu\nu}q^\mu p^\nu$ sum rules satisfy the criteria while the $i\gamma_5$ sum rules beyond the chiral limit do not. For the i\gamma_5\fslash{p} sum rules, the large continuum contributions prohibit reliable prediction for the couplings. Thus, the $\gamma_5\sigma_{\mu\nu}q^\mu p^\nu$ structure seems pertinent for realistic predictions. In the SU(3) limit, we identify the OPE terms responsible for the $F/D$ ratio. We then study the dependence of the ratio on the baryon interpolating fields. We conclude the ratio $F/D \sim 0.6-0.8$ for appropriate choice of the interpolating fields.Comment: To be published in Phys.Rev.C ; 21 pages,8 figures, revtex ; references are adde

Split-belt walking:An experience that is hard to forget

BACKGROUND. The common paradigm to study the adaptability of human gait is split-belt walking. Short-term savings (minutes to days) of split-belt adaptation have been widely studied to gain knowledge in locomotor learning but reports on long-term savings are limited. Here, we studied whether after a prolonged inter-exposure interval (three weeks), the newly acquired locomotor pattern is subject to forgetting or that the pattern is saved in long-term locomotor memory. RESEARCH QUESTION. Can savings of adaptation to split-belt walking remain after a prolonged interexposure interval of three weeks? METHODS. Fourteen healthy adults participated in a single tenminute adaptation session to split-belt walking and five-minute washout to tied-belt walking. They received no training after the first exposure and returned to the laboratory exactly three weeks later for the second exposure. To identify the adaptation trends and quantify saving parameters we used Singular Spectrum Analysis, a non-parametric, data-driven approach. We identified trends in step length asymmetry and double support asymmetry, and calculated the adaptation volume (reduction in asymmetry over the course of adaptation), and the plateau time (time required for the trend to level off). RESULTS. At the second exposure after three weeks, we found substantial savings in adaptation for step length asymmetry volume (61.6% – 67.6% decrease) and plateau time (76.3% decrease). No differences were found during washout or in double support asymmetry. SIGNIFICANCE. This study shows that able-bodied individuals retain savings of split-belt adaptation over a three-week period, which indicates that only naïve split-belt walkers should be included in split-belt adaptation studies, as previous experience to split-belt walking will not be washed out, even after a prolonged period. In future research, these results can be compared with long-term savings in patient groups, to gain insight into factors underlying (un)successful gait training in rehabilitation

“A turn in the road, but still a rough journey” - Parent and child perspectives of outcomes after pre-adolescent inpatient psychiatric admission

Background Research regarding the outcomes of child and adolescent psychiatric inpatients appears insufficient and neglected. Where data are available, the majority of studies focus on adolescents. This study aimed (a) to describe child and parental perspectives of short-, medium- and long-term outcomes of children who have had a pre-adolescent inpatient psychiatric admission, and (b) to analyse these dyadic experiential data to identify outcome variables of importance to families and service users that could be used in future outcomes-based research. Methods The study employed a qualitative methodology, using semi-structured in-depth interviews of ten parent-child dyads to (a) collect the perspectives of children who have had an inpatient psychiatric admission at a pre-adolescent unit and their parents, and (b) to analyse the experiences of inpatient admission and perceived outcomes after discharge using thematic analysis. Results Overall, inpatient psychiatric admission was viewed as a positive and empowering experience by parents and children. Clear short-term benefits were reported as a result of new diagnoses, medications and new skills gained through the admission process. More than half of parent-child dyads reported long-term benefits, but many families commented on ongoing challenges. Thematic analysis identified diagnostic certainty, acquisition of cognitive and behavioural skills, appropriate educational environment, peer relationships, sustained follow-up and medication management, and parent-child relationships, as important contributors to outcomes. Importantly, the presence or lack of these elements influenced outcomes. Conclusions The study explored parent-child dyadic perspectives about their experiences of inpatient mental health admissions for pre-adolescents and perceived outcomes after admission. The majority of families found inpatient admission positive and helpful, and thematic analysis identified a number of functional variables that may predict outcome. However, positive outcomes were associated with ongoing difficulties over time, as indicated by the theme “a turn in the road, but still a rough journey”

Peritoneal Protein Losses and Cytokine Generation in Automated Peritoneal Dialysis with Combined Amino Acids and Glucose Solutions

Objectives. Protein-energy malnutrition as a consequence of deficient protein intake frequently occurs in peritoneal dialysis (PD) patients. Previously, we showed that peritoneal dialysate containing a mixture of amino acids (AA) and glucose has anabolic effects. However AA-dialysate has been reported to increase intraperitoneal protein and AA losses and the release of proinflammatory cytokines (interleukine-6 (IL-6) and tumor necrosis factor alpha (TNFα)). We investigated the effect of AA plus glucose (AAG) solutions on peritoneal protein losses and cytokine generation. Methods. In 6 patients on standard automated peritoneal dialysis (APD) 12 APD sessions of 6 cycles each were performed during the night using dialysate containing 1.1% AA plus glucose or glucose alone as control. Protein losses and TNFα and IL-6 concentrations were measured in dialysates separately collected from nightly cycling and daytime dwell. Results. The 24 hour-protein losses with AAG (median 6.7 g, range 4.7–9.4 g) were similar to control dialysate (median 6.0 g, range 4.2–9.2 g). Daytime dialysate IL-6 levels were higher after nightly AAG dialysis than after control dialysis (142 pg/ml and 82 pg/ml, respectively, P<.05). TNFα concentrations were very low. Conclusion. Nightly APD with amino acids containing dialysate was associated with an increase in peritoneal IL-6 generation during the day. The addition of AA to standard glucose dialysis solutions did not induce a significant increase of peritoneal protein losses

Child health, infant formula funding and South African health professionals: Eliminating conflict of interest

Despite clear evidence of the benefits of exclusive and continued breastfeeding for children, women and society, far too few children in South Africa (SA) are breastfed. One of the major impediments to improving this situation is the continued and aggressive marketing of breastmilk substitutes (BMSs) and infiltration of the BMS industry into contexts with exposure to health professionals. In this article we, as academics, practitioners and child health advocates, describe contraventions of the regulations that protect breastfeeding in SA and argue that bold, proactive leadership to eliminate conflict of interest in respect of the BMS industry is urgently required, together with far greater investments in proven interventions to promote and support breastfeeding

Hyperon-nucleon scattering and hyperon masses in the nuclear medium

We analyze low-energy hyperon-nucleon scattering using an effective field theory in next-to-leading order. By fitting experimental cross sections for laboratory hyperon momenta below 200 MeV/c and using information from the hypertriton we determine twelve contact-interaction coefficients. Based on these we discuss the low-density expansion of hyperon mass shifts in the nuclear medium.Comment: 10 pages, 2 figure

Semiclassical quantization of SU(3) skyrmions

Semiclassical quantization of the SU(3)-skyrmions is performed by means of the collective coordinate method. The quantization condition known for the SU(2)-solitons quantized with SU(3) collective coordinates is generalized for the SU(3) skyrmions with strangeness content different from zero. Quantization of the dipole-type configuration with large strangeness content found recently is considered as an example, the spectrum and the mass splitting of the quantized states are estimated. The energy and baryon number density of SU(3) skyrmions are presented in the form emphasizing their symmetry in different SU(2) subgroups of SU(3), and the lower boundary for the static energy of SU(3) skyrmions is derived.Comment: 16 pages, 2 figures (available upon request). Submitted to JETP on May 6, 1997; in print. A preliminary short version of this paper is hep-th/960916

Child health, infant formula funding and South African health professionals: Eliminating conflict of interest

Letters by Van Niekerk and Khan on article by Lake et al. (Lake L, Kroon M, Sanders D, et al. Child health, infant formula funding and South African health professionals: Eliminating conflict of interest. S Afr Med J 2019;109(12):902-906. https://doi.org/10.7196/SAMJ.2019.v109i12.14336); and response by Lake et al

Soft-core hyperon-nucleon potentials

A new Nijmegen soft-core OBE potential model is presented for the low-energy YN interactions. Besides the results for the fit to the scattering data, which largely defines the model, we also present some applications to hypernuclear systems using the G-matrix method. An important innovation with respect to the original soft-core potential is the assignment of the cut-off masses for the baryon-baryon-meson (BBM) vertices in accordance with broken SU(3)$_F$, which serves to connect the NN and the YN channels. As a novel feature, we allow for medium strong breaking of the coupling constants, using the $^3P_0$ model with a Gell-Mann--Okubo hypercharge breaking for the BBM coupling. We present six hyperon-nucleon potentials which describe the available YN cross section data equally well, but which exhibit some differences on a more detailed level. The differences are constructed such that the models encompass a range of scattering lengths in the $\Sigma N$ and $\Lambda N$ channels. For the scalar-meson mixing angle we obtained values $\theta_S=37$ to 40 degrees, which points to almost ideal mixing angles for the scalar $q\bar{q}$ states. The G-matrix results indicate that the remarkably different spin-spin terms of the six potentials appear specifically in the energy spectra of $\Lambda$ hypernuclei.Comment: 37 pages, 4 figure