26 research outputs found
Single- and Multi-carrier Quadrature Amplitude Modulation: Principles and Applications for Personal Communications, WATM and Broadcasting: 2nd
No full textSingle- and Multi-carrier Quadrature Amplitude Modulation Principles and Applications for Personal Communications, WLANs and Broadcasting L. Hanzo Department of Electronics and Computer Science, University of Southampton, UK W. Webb Motorola, Arlington Heights, USA formerly at Multiple Access Communications Ltd, Southampton, UK T. Keller Ubinetics, Cambridge Technology Centre, Melbourn, UK formerly at Department of Electronics and Computer Science, University of Southampton, UK Motivated by the rapid evolution of wireless communication systems, this expanded second edition provides an overview of most major single- and multi-carrier Quadrature Amplitude Modulation (QAM) techniques commencing with simple QAM schemes for the uninitiated through to complex, rapidly-evolving areas, such as arrangements for wide-band mobile channels. Targeted at the more advanced reader, the multi-carrier modulation based second half of the book presents a research-orientated outlook using a variety of novel QAM-based arrangements. * Features six new chapters dealing with the complexities of multi-carrier modulation which has found applications ranging from Wireless Local Area Networks (WLAN) to Digital Video Broadcasting (DVB) * Provides a rudimentary introduction for readers requiring a background in the field of modulation and radio wave propagation * Discusses classic QAM transmission issues relevant to Gaussian channels * Examines QAM-based transmissions over mobile radio channels * Incorporates QAM-related orthogonal techniques, considers the spectral efficiency of QAM in cellular frequency re-use structures and presents a QAM-based speech communications system design study * Introduces Orthogonal Frequency Division Multiplexing (OFDM) over both Gaussian and wideband fading channels By providing an all-encompassing self-contained treatment of single- and multi- carrier QAM based communications, a wide range of readers including senior undergraduate and postgraduate students, practising engineers and researchers alike will all find the coverage of this book attractive
"In vitro" reconstitution of "trans"-Golgi exit and the effect of GAG attachment on protein sorting
No full textThe trans-Golgi network is one of the main sorting stations for proteins and lipids in the eukaryotic endomembrane system. Yet, the mechanisms for sorting and transport out of the trans-Golgi network remain poorly understood. In this work, an in vitro procedure to reconstitute carrier formation at the trans-Golgi was established. Using this assay, it could be shown that formation of carriers containing the asialoglycoprotein receptor H1 and the cation dependent mannose 6-phosphate receptor is independent of the clathrin machinery, but dependent on GTP hydrolysis. This is in contrast to the common notion that the mannose 6phosphate receptor exits the Golgi in clathrin coated vesicles, but is consistent with recent evidence for tubular export carriers or maturation. The assay is based on sulfation, which can only take place in the trans-Golgi and thus defines the starting compartment. To improve the radioactive sulfation signal in the assay, a novel tag was developed that contains an attachment site for glycosaminoglycans (long, linear and heavily sulfated carbohydrate polymers). To investigate the influence of glycosaminoglycan attachment on protein sorting, biosynthetic exocytosis, endocytosis, endocytic recycling, and overall stability of H1 with or without glycan was examined. While stability and recycling were unaffected, exocytosis was accelerated and endocytosis was slowed down by carbohydrate attachment. Endocytosis was impaired due to interactions of glycosaminoglycan with the extracellular matrix, but the alteration of exocytosis rate requires further investigation, as it suggests that the glycan diverts the protein to a different sorting route
Health and Individual and Community Characteristics: A Research Protocol
No full textPopulation health policies tend to target communities to enhance the health status of individuals. However, little is known about the effects of community or socio-economic environmental variables on individual health characteristics and behaviour patterns. This paper outlines procedures designed to examine the contribution of context in producing health.health policy
Guide to the nature and methods of analysis of the clay fraction of tephras from the South Auckland region, New Zealand.
No full textThe manual outlines some of the more common laboratory procedures available for qualitatively and quantitatively analysing the composition of the tephric clays, many of which are difficult to determine because of their short range order or 'amorphous' nature. Techniques described and assessed in terms of their rapidity and quantitativeness include XRD, IR, DTA, TEM and SEM, sodium fluoride reactivity, chemical dissolution analyses, and surface area measurements. No one technique alone produces a definitive clay fraction analysis of tephric deposits. -from Author
Fisiologia e metabolismo da embriogênese somática e zigótica de Acca sellowiana (Berg) Burret (MYRTACEAE)
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-graduação em Recursos Genéticos Vegetais, Florianópolis, 2008The Acca sellowiana somatic embryogenesis model system has been extensively studied in the last years. Although somatic embryos are obtained in high frequency and show to be morphologically normal, their conversion rates are still low. The ABA is a plant hormone known to induce a cascade of important events that result in a normal germination The Fluridone (1-metil-3-fenil-5-[3-(trifluormetil)-fenil]-4(1H)-piridinona), is a inhibitor of carotenogenesis, ABA synthesis and derivatives, being compared to GA3 in its physiological effects. Thus, in the present work we attempted to study the role of Fluridone in the conversion of Acca sellowiana somatic embryos. Somatic embryos were from mature zygotic embryos inoculated in LPm culture medium supplemented with maltose (3%); Morel vitamins, phytagel (0.2%), and 2,4 - D (20ìM). Somatic embryos in torpedo, precotyledonary and cotyledonary stages were placed in Petri dishes containing 30 mL of growing medium LPm medium plus sucrose (3%), active charcoal (1.5%), Morel vitamins, and supplemented with BAP (0.5 ìM), GA3 (1 ìM) and Fluridone (0, 1. 5 and 10 ìM). Complementarily to the same basal culture medium with BAP (0.5 ìM), GA3 (1 ìM), 0.25; 0.5; 1; 1.5 and 2ìM of Fluridone was added. The cultures were incubated in culture room at a temperature of 25 ± 2 °C temperature, under photoperiod of 16 h;, and 50 ìmol m-2s-1 light intensity The rate conversion to plantlets was evaluated to 15, 30 and 45 days. The largest rate of embryo conversion resulted from the treatment with 1ìM of Fluridone. The embryo conversion was suppressed in response to Fluridone at 2 and 10 ìM. Acca sellowiana somatic embryos show of sensitivity to Fluridone, thus confirming its antagonism with ABA
Pharmacokinetic/pharmacodynamic modelling approaches in paediatric infectious diseases and immunology
No full textPharmacokinetic/pharmacodynamic (PKPD) modelling is used to describe and quantify dose-concentration-effect relationships. Within paediatric studies in infectious diseases and immunology these methods are often applied to developing guidance on appropriate dosing. In this paper, an introduction to the field of PKPD modelling is given, followed by a review of the PKPD studies that have been undertaken in paediatric infectious diseases and immunology. The main focus is on identifying the methodological approaches used to define the PKPD relationship in these studies. The major findings were that most studies of infectious diseases have developed a PK model and then used simulations to define a dose recommendation based on a pre-defined PD target, which may have been defined in adults or in vitro. For immunological studies much of the modelling has focused on either PK or PD, and since multiple drugs are usually used, delineating the relative contributions of each is challenging. The use of dynamical modelling of in vitro antibacterial studies, and paediatric HIV mechanistic PD models linked with the PK of all drugs, are emerging methods that should enhance PKPD-based recommendations in the future
Polinização por abelhas em Aechmea caudata lindm., uma bromélia com características ornitófilas, na ilha de Santa Catarina, Sul do Brasil
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-graduação em Biologia Vegetal, Florianópolis, 2009A maioria das espécies de Bromeliaceae é polinizada por beija-flores, mas borboletas e, principalmente, abelhas estão entre os visitantes florais mais freqüentes em algumas bromélias ornitófilas de corola curta. A importância dos visitantes florais para a polinização de Aechmea caudata foi determinada através da freqüência e a eficiência de polinização desses visitantes. Foi determinado também o sistema reprodutivo e a taxa natural de frutificação e produção de sementes, além do registro da fenologia de A. caudata. Os estudos foram desenvolvidos em uma área secundária de Mata Atlântica na Ilha de Santa Catarina. Ao longo de um transecto (1 ha), foram realizadas 62 horas de observações focais entre março de 2008 e março de 2009. Aechmea caudata produziu néctar ao longo de toda a antese (das 05:00 às 20:00 h) e é uma espécie auto-incompatível, portanto, dependente de polinizadores para a formação de sementes. No total, 16 espécies de quatro ordens animais foram registradas nas flores obtendo o néctar e pólen em visitas legítimas. As abelhas (nove espécies) foram as mais diversas e freqüentes, com 91% do total de 647 visitas, enquanto as cinco espécies de borboletas representaram apenas 6,7% das visitas, além de uma única visita de Coereba flaveola (cambacica). Apesar de apresentar características ornitófilas, A. caudata foi visitada pelo beija-flor Thalurania glaucopis apenas ocasionalmente (16 visitas). Essa baixa taxa de visitação pode estar associada a uma pequena população de T. glaucopis na área, cuja demanda energética é suportada por outras fontes alimentares sem a necessidade de competir com as abelhas pelo néctar de A. caudata. Contrariamente ao hipotetizado, os testes de eficiência de polinização demonstraram que as visitas do beija-flor não resultaram em polinização cruzada; apenas as visitas de Bombus morio promoveram a formação de sementes. Estes resultados evidenciam a importância de co-polinizadores para espécies de plantas cujos polinizadores primários estão ausentes ou em densidades populacionais baixas em determinadas áreas e confirmam que sistemas de polinização mista podem ser vantajosos e ocorrer em plantas aparentemente especializadas, como as bromélias
