Performance Comparison of Terrestrial DVB Detection using LDPC and Turbo Codes

Last-generation and future wireless communication standards, such as DVB-T2 or DVB-NGH, are including multi-antenna transmission and reception in order to increase bandwidth efficiency and receiver robustness. The main goal is to combine diversity and spatial multiplexing in order to fully exploit the multiple-input multiple output (MIMO) channel capacity. Full-rate full-diversity (FRFD) space-time codes (STC) such as the Golden code are studied for that purpose. However, despite their larger achievable capacity, most of them present high complexity for soft detection, which hinders their combination with soft-input decoders in bit-interleaved coded modulation (BICM) schemes. This article presents a low complexity soft detection algorithm for the reception of FRFD space-frequency block codes in BICM orthogonal frequency division multiplexing (OFDM) systems and gives the performance comparision using Ldpc and Turbo codes. The proposed detector maintains a reduced and fixed complexity, avoiding the variable nature of the list sphere decoder (LSD) due to its dependence on the noise and channel conditions. Complexity and simulation based performance results are provided which show that the proposed detector performs close to the optimal log-maximum a posteriori (MAP) detection in a variety of DVB-T2 broadcasting scenarios

Essential role for cholesterol in the delivery of exogenous antigens to the MHC class I-presentation pathway

Cross-presentation, which is crucial for the generation of immunity against virus-infected and tumor cells, requires exogenous antigens to be internalized into antigen-presenting cells (APCs) followed by translocation to the cytosol by unknown mechanisms. One important entry route for such antigens is macropinocytosis. We here describe that cholesterol is essential for cross-presentation of antigens loaded via macropinocytosis into APCs. Modification of antigens by palmitoylation to target antigens to cholesterol-enriched plasma membrane domains resulted in a dramatically increased T cell activation. These results define cholesterol as an essential factor for cross-presentation and suggest that specific modification of antigens to increase their affinity for cholesterol may be utilized to enhance immunit

Shunt Active and Series Active Filters-Based Power Quality Conditioner for Matrix Converter

This paper proposes a series active filter and shunt active filter to minimize the power quality impact present in matrix converters instead of passive filter. A matrix converter produces significant harmonics and nonstandard frequency components into load. The proposed system compensates the sag and swell problems efficiently in matrix converter. The proposed system has been tested and validated on the matrix converter using MATLAB/Simulink software. Simulated results confirm that the active power filters can maintain high performance for matrix converter

Random hypergraph irregularity

A hypergraph is k-irregular if there is no set of k vertices all of which have the same degree. We asymptotically determine the probability that a random uniform hypergraph is k-irregular

TOR controla el estado de fosforilación de la chaperona BiP en Chlamydomonas reinhardtii

1 página.La quinasa TOR (Target Of Rapamycin) integra señales nutricionales y de estrés para controlar de forma coordinada el crecimiento celular en eucariotas. TOR se asocia con otras proteínas conservadas para constituir dos complejos de señalización denominados TORC1 y TORC2.Peer reviewe

Inhibition of protein synthesis by TOR inactivation revealed a conserved regulatory mechanism of the BiP chaperone in Chlamydomonas

The target of rapamycin (TOR) kinase integrates nutritional and stress signals to coordinately control cell growth in all eukaryotes. TOR associates with highly conserved proteins to constitute two distinct signaling complexes termed TORC1 and TORC2. Inactivation of TORC1 by rapamycin negatively regulates protein synthesis in most eukaryotes. Here, we report that down-regulation of TOR signaling by rapamycin in the model green alga Chlamydomonas reinhardtii resulted in pronounced phosphorylation of the endoplasmic reticulum chaperone BiP. Our results indicated that Chlamydomonas TOR regulates BiP phosphorylation through the control of protein synthesis, since rapamycin and cycloheximide have similar effects on BiP modification and protein synthesis inhibition. Modification of BiP by phosphorylation was suppressed under conditions that require the chaperone activity of BiP, such as heat shock stress or tunicamycin treatment, which inhibits N-linked glycosylation of nascent proteins in the endoplasmic reticulum. A phosphopeptide localized in the substrate-binding domain of BiP was identified in Chlamydomonas cells treated with rapamycin. This peptide contains a highly conserved threonine residue that might regulate BiP function, as demonstrated by yeast functional assays. Thus, our study has revealed a regulatory mechanism of BiP in Chlamydomonas by phosphorylation/dephosphorylation events and assigns a role to the TOR pathway in the control of BiP modification. © 2011 American Society of Plant Biologists. All Rights Reserved.ACKNOWLEDGMENTS We thank Mark Rose for providing MS10 and kar2-159 yeast strains, Robbie Loewith for critical comments on the manuscript, Jesús de la Cruz and Dieter Kessler for providing the yeast heterozygous KAR2::kar2 mutant, and Néstor García and Ralf Wellinger for micromanipulation of yeast cells.Peer Reviewe

The effects of m-learning on motivation, achievement and well-being: A Self-Determination Theory approach

From the lens of Self‐Determination Theory, this study investigated the effects of a mobile application tool for identifying species on biology students’ achievement and well‐being. It was hypothesized that the mobile application, compared to a textbook, would enhance feelings of competence and autonomy and, in turn, intrinsic motivation, positive affect and achievement, because the mobile application’s built‐in functions provide students with choice and volition, informational feedback, and optimal challenges. Fifty‐eight second‐year students were randomly assigned to use either the mobile application or a textbook for a learning task. Well‐being was assessed before and after the learning task, and intrinsic motivation, perceived competence, perceived autonomy and achievement were assessed after the task. Results indicated that the mobile application, relative to the textbook, produced higher levels of students’ perceived competence, perceived autonomy and intrinsic motivation. Further, the mobile application had indirect effects on positive affect through autonomy, competence and intrinsic motivation, and on achievement through competence