Design and Analysis of OFDM System for Powerline Based Communication

Research on digital communication systems has been greatly developed in the past few years and offers a high quality of transmission in both wired and wireless communication environments. Coupled with advances in new modulation techniques, Orthogonal Frequency Division Multiplexing (OFDM) is a well-known digital multicarrier communication technique and one of the best methods of digital data transmission over a limited bandwidth [1]. In this paper, design and analysis of OFDM system for powerline based communication is proposed. In doing so, MATLAB and embedded Digital Signal Processing (DSP) systems are used to simulate the operation of virtual transmitter and receiver. The performance of the system design is then analysed by adding noise (additive white Gaussian noise, Powerline coloured background noise and Middleton Class A noise) in an attempt to corrupt the signal. In this paper results will show that performance is improved by using lower order modulation formats e.g. Binary Phase Shift Keying (BPSK), QPSK, etc. compared to the higher modulation schemes e.g. 64 Quadrature Amplitude Modulation (QAM); as they offer lower data rates but are more robust in the presence of noise. The performance study of OFDM scheme is also examined with and without presence of noise and application of forward error correction (FEC)

Scalable and Robust Community Detection with Randomized Sketching

This paper explores and analyzes the unsupervised clustering of large partially observed graphs. We propose a scalable and provable randomized framework for clustering graphs generated from the stochastic block model. The clustering is first applied to a sub-matrix of the graph's adjacency matrix associated with a reduced graph sketch constructed using random sampling. Then, the clusters of the full graph are inferred based on the clusters extracted from the sketch using a correlation-based retrieval step. Uniform random node sampling is shown to improve the computational complexity over clustering of the full graph when the cluster sizes are balanced. A new random degree-based node sampling algorithm is presented which significantly improves upon the performance of the clustering algorithm even when clusters are unbalanced. This algorithm improves the phase transitions for matrix-decomposition-based clustering with regard to computational complexity and minimum cluster size, which are shown to be nearly dimension-free in the low inter-cluster connectivity regime. A third sampling technique is shown to improve balance by randomly sampling nodes based on spatial distribution. We provide analysis and numerical results using a convex clustering algorithm based on matrix completion

Self-perceived cognitive decline, neuropsychological functioning, and depressive symptoms in HIV+ Spanish-speakers

Within the United States, HIV is a growing epidemic that has important neuropsychological and functional consequences. Early detection and treatment of HIV-associated neurocognitive disorder (HAND) is associated with better outcomes. In major metropolitan areas such Los Angeles County, HIV disproportionately impacts the Latino community. For those individuals who are primarily Spanish-speakers, there may be limited access to comprehensive neuropsychological assessment in the preferred language. Consequently, self-reports of cognitive functioning are often relied on to help determine the presence of HAND. However, self-reports of cognitive decline may be influenced by factors such as depressed mood, variable motivation, and culture, raising important validity questions. To date, relatively few studies have focused on the combined use of Spanish-language, self-report measures of cognitive functioning and mood among primarily Spanish-speaking, HIV-positive individuals. The aim of this study was to explore the relationships among self-reported cognitive decline, neuropsychological functioning, and mood symptoms within this population. Archival data from a sample of 100 HIV+, primarily Spanish-speaking adults who participated in the parent study at a major medical center in Los Angeles were examined. Measures included Spanish-language versions of the Beck Depression Inventory, Cognitive Difficulties Scale- Patient Version, Medical Outcomes HIV Health Survey, and an acculturation measure. An array of neuropsychological measures was used to determine the presence of HAND. It was predicted that depressive symptoms would be positively associated with self-reported cognitive decline. This hypothesis was strongly supported by the results of correlational analysis. The results also showed that for individuals with HAND, the difference in BDI scores between participants with cognitive complaints and those without varied depending on whether the MOS-HIV or the CDS was used to assess cognitive complaints. The analyses revealed no significant impact of acculturation on the relationships among cognitive complaints, neuropsychological functioning, and depressive symptoms. The results of the present study highlight the complex relationship between neuropsychiatric and neuropsychological functioning in Spanish-speaking individuals infected with HIV. Clinical implications and limitations of the study are addressed. Future research that incorporates objective measures of neuropsychological functioning, the input of collateral informants, and self-report measures of mood and functional decline is recommended

Signal transduction pathways in hepatocyte cell death:new targets for therapy

Cholestatische en steatotische leverziekten hebben een significant aandeel in het totaal van leverziekten. Zowel cholestatische als steatotische leverziekten zijn geassocieerd met hoge morbiditeit en sterftecijfers. Bestaande therapieën zijn of niet erg effectief of zijn geassocieerd met hun eigen problematiek. Beide ziektegroepen worden gekarakteriseerd door een geleidelijke en progressief verlies van gezonde hepatocyten wat leidt tot leverontsteking, fibrogenese en eindstadium leverziekte. Hepatocyten celdood kan via apoptose of necrose (of een tussenvorm) gaan. De kennis van de cellulaire mechanismen die dood en overleven van levercellen reguleren is van klinisch en wetenschappelijk belang voor de ontwikkeling van nieuwe therapeutische strategieën. Het doel van dit proefschrift is de mechanismen van celdood in hepatocyten te verhelderen en op die manier strategieën te ontwikkelen om de hepatocyten te beschermen en leverschade te voorkomen. Drie modellen van hepatocyten celdood zijn bestudeerd: glycochenodeoxycholzuur (GCDCA)-geïnduceerde celdood als model voor galzuur toxiciteit, tumor necrose factor α (TNF-α)/ Actinomycine D (ActD, een transcriptie remmer) als model voor cytokine-geïnduceerde toxiciteit en menadion-geïnduceerde celdood (menadion is een superoxide anion donor) als model voor oxidatieve stress geïnduceerde toxiciteit. Deze modellen zijn klinisch relevant want al deze toxische stimuli zijn in verhoogde mate aanwezig in de meeste leverziekten. Dit proefschrift beschrijft dat hepatocyten celdood en overleving zijn gereguleerd door middel van intracellaire organellen (zoals mitochondria en het endoplasmatisch reticulum), membraan gebonden receptoren (zoals GPCRs en EGFR) en cel overlevings routes (zoals ERK, PI3K en PKC)