An efficient CDMA decoder for correlated information sources

We consider the detection of correlated information sources in the ubiquitous Code-Division Multiple-Access (CDMA) scheme. We propose a message-passing based scheme for detecting correlated sources directly, with no need for source coding. The detection is done simultaneously over a block of transmitted binary symbols (word). Simulation results are provided demonstrating a substantial improvement in bit-error-rate in comparison with the unmodified detector and the alternative of source compression. The robustness of the error-performance improvement is shown under practical model settings, including wrong estimation of the generating Markov transition matrix and finite-length spreading codes.Comment: 11 page

Parallel vs. Sequential Belief Propagation Decoding of LDPC Codes over GF(q) and Markov Sources

A sequential updating scheme (SUS) for belief propagation (BP) decoding of LDPC codes over Galois fields, $GF(q)$, and correlated Markov sources is proposed, and compared with the standard parallel updating scheme (PUS). A thorough experimental study of various transmission settings indicates that the convergence rate, in iterations, of the BP algorithm (and subsequently its complexity) for the SUS is about one half of that for the PUS, independent of the finite field size $q$. Moreover, this 1/2 factor appears regardless of the correlations of the source and the channel's noise model, while the error correction performance remains unchanged. These results may imply on the 'universality' of the one half convergence speed-up of SUS decoding

Pengelompokan Kecamatan Di Kabupaten Toraja Utara Berdasarkan Hasil Produksi Pertanian Menggunakan Analisis Gerombol

Peran sektor pertanian dalam pembangunan ekonomi antara lain. Sebagai penyedia pangan, sebagai sumber tenaga kerja bagi sektor perekonomian lain, sebagai sumber kapital bagi pertumbuhan ekonomi modern khususnya dalam tahap awal pembangunan, sebagai sumber devisa dan masyarakat pedesaan merupakan pasar bagi produk yang dihasilkan dari sektor indutri di perkotaan. Penelitian ini bertujuan untuk mengelompokan Kecamatan di Kabupaten Toraja Utara berdasarkan potensi sektor pertanian. Dalam penelitian ini menggunakan analisis gerombol dengan metode single linkage dan menggunakan pengukuran jarak squared euclidean. Hasil penelitian menunjukan bahwa pada sektor pertanian di Toraja Utara terbentuk empat gerombol

Release of tumor necrosis factor-alpha and prostanoids in whole blood cultures after in vivo exposure to low-dose aspirin.

BACKGROUND: The preventive effect of low-dose aspirin in cardiovascular disease is generally attributed to its antiplatelet action caused by differential inhibition of platelet cyclooxygenase-1. However, there is evidence that aspirin also affects release of inflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha). It is not known whether this is caused by direct action on the cytokine pathway or indirectly through cyclooxygenase inhibition and altered prostanoid synthesis, or both. METHODS: We assessed the capacity of lipopolysaccharide-activated leukocytes in whole blood cultures of eight healthy subjects following a single oral dose of 80 mg aspirin to release TNF-alpha, prostanoid E2 (PGE2) and prostanoid I2 (PGI2), and thromboxane A2 (TXA2). TNF-alpha and prostanoids were determined by enzyme-linked immunoassays. RESULTS: In seven subjects, TNF-alpha release in blood cultures decreased 24h after intake of aspirin. The effect of aspirin on prostanoid release was assessed in three individuals: PGE2 increased in all subjects, PGI2 increased in two and remained unchanged in one, and TXA2 was reduced in two and unchanged in one individual The presence of DFU, a specific inhibitor of cyclooxygenase 2, did not affect the reduction of TNF-alpha release by aspirin, but abolished prostanoid production in all three individuals. Conclusion: The capacity of activated leukocytes to release TNF-alpha is reduced by ingestion of low-dose aspirin, independent of changes in prostanoid biosynthesis

Hypoxia modulates human eosinophil function

<p>Abstract</p> <p>Background</p> <p>Eosinophils are involved in various inflammatory processes including allergic inflammation during which angiogenesis has been documented. Angiogenesis is most likely connected to the hypoxia which characterizes inflamed tissues. Eosinophils produce VEGF and are pro-angiogenic. However, to the best of our knowledge no study has been performed to verify the existence of a direct link between eosinophils, hypoxia and angiogenesis in allergic inflammation.</p> <p>Objective</p> <p>To characterize eosinophil function and angiogenic potential under hypoxic conditions.</p> <p>Methods</p> <p>Human peripheral blood eosinophils were cultured in normoxic or hypoxic conditions with or without cytokines. Viability and apoptosis were assessed by Annexin V/PI staining. Anti- or pro-apoptotic protein levels, HIF-1α levels and MAPK phosphorylation were analyzed by immunoblot analysis. Angiogenic mediator release was evaluated by ELISA.</p> <p>Results</p> <p>Hypoxic eosinophils were more viable than normoxic ones after up to three days. In addition in hypoxia, anti-apoptotic Bcl-XL protein levels increased more than pro-apoptotic Bax levels. Hypoxia increased VEGF and IL-8 release. In hypoxic eosinophils high levels of HIF-1α were observed, particularly in the presence of GM-CSF. MAPK, particularly ERK1/2 inhibitors, decreased hypoxia-mediated VEGF release and HIF-1α expression.</p> <p>Conclusion</p> <p>Eosinophils respond to hypoxia by up-regulation of survival and of some of their pro-angiogenic functions indicating a correlation between eosinophilic inflammation and angiogenesis.</p

Analisis Kandungan Karotenoid Ekstrak Kasar Buah Pisang Tongkat Langit (Musa Troglodytarum) dengan Menggunakan Spektroskopi Nir (Near Infrared)

Kandungan karotenoid yang terdapat dalam buah-buahan dan sayuran, berperan penting dalam mencegah penyakit manusia, termasuk penyakit kardiovaskuler, kanker dan penyakit kronis lainnya. Namun, banyak metode yang digunakan dalam penentuan komposisi kimia khususnya untuk bahan makanan membutuhkan waktu yang lama serta biaya cukup mahal. Saat ini sejumlah teknik instrumentasi telah dikembangkan untuk menentukan kandungan kimia dengan cepat. Salah satu contoh adalah teknik pengukuran dengan menggunakan spektroskopi NIR. Dalam penelitian ini, spektroskopi NIR digunakan untuk analisis pendugaan karotenoid ekstrak kasar buah pisang tongkat langit (Musa troglodytarum) yang panjang dan pendek. Hasil yang diperoleh menunjukkan pisang tongkat langit mengandung β-karoten, sebab pada area bilangan gelombang 5000 hingga 5500 cm-1 terlihat adanya kemiripan antara pola spektrum β-karoten marker dengan pola spektrum pigmen karotenoid pisang tongkat langit

Ultrafast Multiharmonic Plasmon Generation by Optically Dressed Electrons

Interactions between electrons and photons are a source of rich physics from atomic to astronomical scales. Here, we examine a new kind of electron-photon interaction in which an electron, modulated by light, radiates multiple harmonics of plasmons. The emitted plasmons can be femtosecond in duration and nanometer in spatial scale. The extreme subwavelength nature of the plasmons lowers the necessary input light intensity by at least 4 orders of magnitude relative to state-of-the-art strong-field processes involving bound or free electrons. The results presented here reveal a new means of ultrafast (10–1000 fs) interconversion between photonic and plasmonic energy, and a general scheme for generating spatiotemporally shaped ultrashort pulses in optical materials. More generally, our results suggest a route towards realizing analogues of fascinating physical phenomena like nonlinear Compton scattering in plasmonics and nanophotonics with relatively low intensities, slow electrons, and on nanometer length scales.United States. Department of Energy (Grant DE-FG02-97ER25308)United States. Army Research Office (Contract W911NF-18-2-0048)United States. Army Research Office (Contract W911NF-13-D-0001

Constructing “Designer Atoms” via Resonant Graphene-Induced Lamb Shifts

The properties of an electron in an atom or molecule are not fixed; rather they are a function of the optical environment of the emitter. Not only is the spontaneous emission a function of the optical environment, but also the underlying wave functions and energy levels, which are modified by the potential induced by quantum fluctuations of the electromagnetic field. In free space, this modification of atomic levels and wave functions is very weak and generally hard to observe due to the prevalence of other perturbations like fine structure. Here, we explore the possibility of highly tailorable electronic structure by exploiting large Lamb shifts in tunable electromagnetic environments such as graphene, whose optical properties are dynamically controlled via doping. The Fermi energy can be chosen so that the Lamb shift is very weak, but it can also be chosen so that the shifts become more prominent than the fine structure of the atom and even potentially the Coulomb interaction with the nucleus. Potential implications of this idea include being able to electronically shift an unfavorable emitter structure into a favorable one, a new approach to probe near-field physics in fluorescence, and a way to access regimes of physics where vacuum fluctuations are not a weak perturbation but rather the dominant physics. Keywords: graphene plasmonics; Lamb shift; light-matter interactions; quantum electrodynamicsUnited States. Army Research Office (Grant W911NF-13-D-0001)United States. Department of Energy (Award DE-FG02-97ER25308

Tailoring the energy distribution and loss of 2D plasmons

The ability to tailor the energy distribution of plasmons at the nanoscale has many applications in nanophotonics, such as designing plasmon lasers, spasers, and quantum emitters. To this end, we analytically study the energy distribution and the proper field quantization of 2D plasmons with specific examples for graphene plasmons. We find that the portion of the plasmon energy contained inside graphene (energy confinement factor) can exceed 50%, despite graphene being infinitely thin. In fact, this very high energy confinement can make it challenging to tailor the energy distribution of graphene plasmons just by modifying the surrounding dielectric environment or the geometry, such as changing the separation distance between two coupled graphene layers. However, by adopting concepts of parity-time symmetry breaking, we show that tuning the loss in one of the two coupled graphene layers can simultaneously tailor the energy confinement factor and propagation characteristics, causing the phenomenon of loss-induced plasmonic transparency.Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies (W911NF-13-D-0001)United States. Department of Energy. Office of Science. Solid-State Solar Thermal Energy Conversion Center (DESC0001299)National Science Foundation (U.S.) (1122374)National Science Foundation (U.S.) (DMR-1419807)China Scholarship Council (201506320075