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Letteratura scientifica selezionata sul tema "Spread ALOHA"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 20 febbraio 2023

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Articoli di riviste sul tema "Spread ALOHA"

Sasamori, Fumihito, e Fumio Takahata. "Transmission efficiency of spread ALOHA system using unified spread-spectrum code". Electronics and Communications in Japan (Part I: Communications) 79, n. 1 (1996): 107–15. http://dx.doi.org/10.1002/ecja.4410790111.

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Sang Wu Kim. "Stabilization of slotted ALOHA spread-spectrum communication networks". IEEE Journal on Selected Areas in Communications 8, n. 4 (maggio 1990): 555–61. http://dx.doi.org/10.1109/49.54453.

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Gallinaro, Gennaro, Filippo Di Cecca, Maria-Antonietta Marchitti, Riccardo De Gaudenzi e Oscar Del Rio Herrero. "Enhanced spread spectrum ALOHA system level performance assessment". International Journal of Satellite Communications and Networking 32, n. 6 (11 novembre 2013): 485–503. http://dx.doi.org/10.1002/sat.1057.

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De Gaudenzi, Riccardo, Oscar del Rio Herrero e Gennaro Gallinaro. "Enhanced spread Aloha physical layer design and performance". International Journal of Satellite Communications and Networking 32, n. 6 (13 maggio 2014): 457–73. http://dx.doi.org/10.1002/sat.1078.

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Enomoto, Masaru, e Fumio Takahata. "An application of chirp to spread-ALOHA system". Electronics and Communications in Japan (Part I: Communications) 78, n. 1 (gennaio 1995): 72–81. http://dx.doi.org/10.1002/ecja.4410780107.

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Kim, Tae-Joong, Jin-Ho Lee, Byeong-Gwon Kang e Keum-Chan Whang. "CLSP with channel clearance for spread slotted ALOHA network". Electronics Letters 33, n. 18 (1997): 1524. http://dx.doi.org/10.1049/el:19971020.

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Makrakis, D., e K. M. S. Murthy. "Spread slotted ALOHA techniques for mobile and personal satellite communication systems". IEEE Journal on Selected Areas in Communications 10, n. 6 (1992): 985–1002. http://dx.doi.org/10.1109/49.144885.

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Toshimitsu, K., T. Yamazato, M. Katayama e A. Ogawa. "A novel spread slotted Aloha system with channel load sensing protocol". IEEE Journal on Selected Areas in Communications 12, n. 4 (maggio 1994): 665–72. http://dx.doi.org/10.1109/49.286673.

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Jamalipour, A., M. Katayama, T. Yamazato e A. Ogawa. "Transmit permission control on spread ALOHA packets in LEO satellite systems". IEEE Journal on Selected Areas in Communications 14, n. 9 (1996): 1748–57. http://dx.doi.org/10.1109/49.545697.

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Andrenacci, Marco, Gaetano Mendola, Florian Collard, Daniele Finocchiaro e Annamaria Recchia. "Enhanced spread spectrum aloha demodulator implementation, laboratory tests and satellite validation". International Journal of Satellite Communications and Networking 32, n. 6 (novembre 2014): 521–33. http://dx.doi.org/10.1002/sat.1086.

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Più fonti

Tesi sul tema "Spread ALOHA"

Weibing, Fan, e Zhang Qishan. "Capture Method for Spread Spectrum Aloha Signals". International Foundation for Telemetering, 1996. http://hdl.handle.net/10150/611419.

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International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California
The concept and model of Spread Spectrum ALOHA (SS-ALOHA), as an important subject to develop dual-purpose satellite system in China, are described in this paper. The new synchronous code format and method for capturing the SS-ALOHA signals are presented and the process of correlation with surface-audio wave (SAW) is shown. The diagram of fast acquisition system and the results of experiment are given.

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Toshimitsu, Kiyoshi, Takaya Yamazato, Masaaki Katayama e Akira Ogawa. "A Novel Spread Slotted Aloha System with Channel Load Sensing Protocol". IEEE, 1994. http://hdl.handle.net/2237/7070.

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Jamalipour, Abbas, Masaaki Katayama, Takaya Yamazato e Akira Ogawa. "Transmit Permission Control on Spread ALOHA Packets in LEO Satellite Systems". IEEE, 1996. http://hdl.handle.net/2237/7103.

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Kota, S. L. (Sastri L. ). "Quality of Service for Broadband Satellite Internet - ATM and IP Services". Doctoral thesis, University of Oulu, 2003. http://urn.fi/urn:isbn:9514268865.

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Abstract The current Internet infrastructure must be architected to handle future media-rich, and content rich applications. The success of applications such as video-on-demand, multicast and content distribution depends on Quality of Service and bandwidth guarantees. Over the years, the Internet has encompassed many changes in traffic profiles and applications, in bandwidths and utilization, but the future Internet infrastructure necessitates a very different architecture supporting Quality of Service (QoS). A satellite, distinguished by features such as global coverage, bandwidth flexibility, broadcast, multicast, and reliability, is an excellent candidate to provide broadband integrated Internet access. The aim of this thesis is to explore suitability of satellite technologies for broadband Internet services with significant emphasis on the question of defining, assessing, and developing QoS models for satellite ATM and IP broadband networks with and without onboard processing. For the satellite Internet, Transmission Control Protocol (TCP) performance is degraded due to long propagation delays, link errors, and bandwidth asymmetry. In this thesis, for satellite ATM, fundamental questions such as buffer requirements, TCP/ATM efficiency, fairness, and multiple access are addressed through extensive simulations in a quantitative way. Buffer designs for TCP over satellite ATM Unspecified Bit Rate (UBR) service are performed. A buffer size equal to half the round trip delay-bandwidth product of the TCP connections provides high efficiency for TCP over satellite UBR. An extensive TCP analysis via simulation study for various TCP mechanisms and end system policies show that for satellite environment end system policies are more important than switch drop policies in terms of efficiency and fairness for World Wide Web traffic. A bandwidth allocation scheme is proposed and analytical model for supporting voice and video service over a broadband satellite network is developed. The study results demonstrate that non-contiguous allocation can afford higher gain in uplink utilizations. In this thesis, for the first time, Integrated Services and Differentiated Services based QoS architectures for broadband satellite IP networks are proposed and analyzed. In multimedia applications where User Datagram Protocol (UDP) is used along with TCP, a fair excess bandwidth allocation is not possible because TCP is congestion sensitive whereas UDP is congestion insensitive. An extensive simulation model is developed to study the effect of precedence levels for reserved rate utilization and fairness with different buffer management policies. The simulation results indicate that three levels of precedence are required for better utilization. Multiprotocol Label Switching (MPLS) over Satellite network has been proposed and a simulation model developed to study the throughput performance impacts for TCP and UDP. The traffic engineering of MPLS facilitates efficient and reliable network design to optimize the utilization of network resources and enhance the network QoS. A novel Code Division Multiple Access based Spread ALOHA single code multiple access scheme for broadband satellite return channel is proposed as an alternative to Multifrequency-Time Division Multiple Access based Digital Video Broadcasting-Return Channel via Satellite protocol. It is shown through Monte Carlo simulations that throughput for Spread ALOHA One Long Code equivalent to packet length, is better than Spread ALOHA One Code in which spreading sequence repeats every symbol. The reduction of throughput due to multi-user interference for different number of users is shown. Further research on QoS architectures, performance models for TCP enhancements, interworking functions, interoperability, and standardization efforts is included.

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Valdinocci, Dario. "Exploring Mechanisms of Alpha-Synuclein Spread in Parkinson's and Atypical Parkinson's Diseases". Thesis, Griffith University, 2020. http://hdl.handle.net/10072/393604.

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The development of neurodegenerative diseases is an ever increasing risk faced by modern society as aging populations rise globally. For complex diseases such as Alzheimer‟s Disease (AD) or Parkinson‟s Disease (PD) the prospect of finding a cure within the immediate future is unlikely. These complexities arise primarily from the interactions of the protein of interest each of the diseases, which in the case of typical and atypical PD is α-synuclein (α-syn). Thought to be involved in neuronal vesicle recycling in its monomeric α-helical state, change to a β-sheet conformation allows α-syn to misfold, creating oligomers and eventually aggregates which form the initial bedrock for inclusion bodies. One of the more fascinating features of pathological α-syn is the difference in inclusion body composition and cell type affected in typical and atypical PD variants. For instance within Multiple System Atrophy (MSA), an atypical PD variant, α-syn aggregates form Glial Cytoplasmic Inclusions (GCIs) the composition of which differs from the Lewy Bodies (LB) formed in PD, and are largely found in oligodendrocytes. Unlike neurons, oligodendrocytes normally express only minimal amounts of α-syn which does not alter even after GCIs are formed, indicating acquisition of α-syn from an external source. How oligodendrocytes acquire pathological α-syn and the mechanisms by which the protein is able to spread within the central nervous system (CNS) are topics currently with more questions than answers. Thus the primary focus of the thesis is to investigate potential models of α-syn spread in order to develop future novel targets to slow disease progression. The investigations within Chapters 2 and 3 focus on exploring microglial cells as a potential vehicle for α-syn migration within the CNS. Along with the presence of α-syn inclusion bodies, part of the degeneration taking place within MSA is due to the chronic inflammatory activation and actions of the CNS resident immune cell, the microglia. Whilst microglial inflammatory responses play a role in PD, the severity of inflammation is greater in MSA. Microglia possess many traits which contribute to their ability to become a potential transporter of α-syn, including the lack of ability to degrade internalised pathological α-syn variants such as oligomers and aggregates. Post-mortem human MSA brain tissues were examined for evidence of microglial interactions with GCI-affected oligodendrocytes. Not only were interactions between these cells noted in a variety of different tissue regions and patients, but qualitative evidence of microglial migration with internalised α-syn distal from GCI-affected cells was obtained. Whilst these findings suggest that microglia could play a potential role in α-syn spread within the CNS and α-syn occurrence within oligodendrocytes, post-mortem examination is limited to detailing what may occur following the observed interactions. An in vitro assay was developed to investigate α-syn uptake and mobilisation by cells from a point source of immobilized protein. In this assay, monomeric and aggregated α-syn uptake and migration were assessed when exposured to THP-1 monocytes and microglial-like differentiated THP-1 cells. Microglial-like differentiated THP-1 cells were found to show uptake and migration with internalised aggregate α-syn to distal regions, not observed with undifferentiated THP-1 monocytes or monomeric protein. This result indicates that microglia/microglial-like cells are more likely to internalise pathological α-syn such as aggregates than the normal, monomeric form. The greater numbers of differentiated THP-1 with internalised aggregated α-syn indicates that once the protein has been taken up by microglia, then it becomes a transported to distal brain regions. The inability of microglia to degrade aggregated α-syn, similar to microglia within the CNS, likely contributes microglial-mediated α-syn spread. Further testing using highly aggressive proliferating immortalised (HAPI) cells, a rat microglial cell line, was conducted which corroborated the previous findings, indicating that microglia take up the pathological variant of α-syn, mobilizing the protein rather than degrading it. Utilising the same α-syn mobilization assay, inhibition of microtubule instability through the use of the microtubule stabilising agent Epothilone D (EpoD) proved successful in lowering both uptake and mobilization of aggregated α-syn, showing promise as a novel therapy against α-syn spread. Inhibition of the microglial inflammatory response through TAK-242 treatment, a Toll-like Receptor 4 (TLR4) inhibitor, was also trialled to investigate if TLR4 plays a significant role with regards to α-syn uptake and mobilisation. However, unlike EpoD, TAK-242 proved ineffective. For Chapter 4 experimentation focussed on investigating the role of intercellular mitochondrial transfer through tunnelling nanotubes (TnTs) as a potential means of α-syn spread. Pathological α-syn species have been described to bind to intercellularly migrating organelles such as lysosomes for spread to adjacent sites. The role of mitochondria in typical and atypical PD has predominantly focussed on their role in degeneration and as such gaps exist as to mitochondrial function in relation to α-syn propagation. Utilising Stimulated Emission Depletion (STED) super resolution microscopy, SH-SY5Y, 1321N1 and differentiated THP-1 monocultures, as models of neurons, astrocytes and microglia, were each inoculated with aggregated α-syn to examine transfer to adjacent cells via TnTs whilst bound to mitochondria. Under each cell culture condition, the formation of TnT-like structures was observed between adjacent cells, each containing migrating mitochondria with α-syn aggregates bound to the outer mitochondrial membrane. Further exploration of this result through 1321N1 / differentiated THP-1 co-culture showed that this mechanism of α-syn spread is not limited to monoculture conditions and may be a potential mechanism relevant to typical and atypical PD. Knockdown of Miro1, a critical protein bridging mitochondria to the motor adaptor complex for intercellular migration, was performed in order to ascertain if its role is significant in the α-syn spread process and a potential therapeutic target. Miro1 silencing however proved qualitatively ineffective in the prevention of α-syn spread mediated by mitochondria, indicating other factors in addition to Miro1 may be involved in bridging mitochondria to intercellular motor complexes. Taken together these results illustrate the great complexity of mechanisms of α-syn spread and the inherent difficulties associated with attempting to combat them.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Medical Science
Griffith Health
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Cook, Neil T. "Properties of ferrous-based #alpha#-alumina particulate metal matrix composites produced by spray forming". Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311821.

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Landureau, Maud. "Développement d'outils thérapeutiques ciblant les agrégats d'alpha-synucléine dans les synucléinopathies Mapping of Three Alpha-Synuclein Fibrillar Polymorphs Surfaces Internalization and Degradation of Different Alpha-Synuclein Strains by Neurons or Astrocytes". Thesis, université Paris-Saclay, 2021. http://www.theses.fr/2021UPASL022.

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L'agrégation d'alpha-synucléine et la propagation de ces agrégats de neurone à neurone ont, de manière récurrente, été montrées comme étant au cœur du processus physiopathologique de différentes maladies neurodégénératives telles que la maladie de Parkinson, les démences à corps de Lewy ou les atrophies multisystématisées. Bien que ces synucléinopathies aient en commun la présence de dépôts fibrillaires riches en alpha-synucléine, les phénotypes pathologiques sont différents. Notre hypothèse est que la présence de différentes "souches" d'alpha-synucléines fibrillaires présentant différentes affinités, tropismes, propriétés d'internalisation et de propagation pourrait expliquer l'hétérogénéité physiopathologique et clinique retrouvée dans la maladie de Parkinson et les autres synucléinopathies. Le but de ce projet était de déterminer comment interférer avec la liaison et la propagation "prion-like" de ces assemblages d'alpha-synucléines dans les neurones. Dans cet objectif, nous avons caractérisé les surfaces de trois souches d’alpha-synucléine. Dans un premier temps, nous avons mis en place des approches in vitro de protéolyses ménagées et de marquages hydrogène-deutérium combinées à la spectrométrie de masse qui nous ont permis de cartographier la surface d'agrégats fibrillaires d'alpha-synucléines générés in vitro. Dans un second temps, nous avons étudié la prise charge de différentes souches d’alpha-synucléine par des cultures primaires de neurones ou d’astrocytes afin d’analyser les caractéristiques de dégradation des souches in cellulo, liées à leurs spécificités de surface déterminées préalablement. La cartographie réalisée ouvre la voie, à long terme, au développement d’outils diagnostics ou thérapeutiques hautement spécifiques capables de reconnaitre spécifiquement différentes souches d’alpha-synucléine ou d’inhiber la propagation de cellule à cellule de ces agrégats afin de ralentir ou d'arrêter la progression de la maladie
The aggregation of alpha-synuclein and the spread of aggregates from neuron to neuron have been consistently shown to be at the heart of the pathophysiological process of devasting neurodegenerative diseases like Parkinson's disease, dementia with Lewy bodies or multiple system atrophy. While fibrillar alpha-synuclein rich deposits are a common hallmark of synucleinopathies, distinct pathological phenotypes are observed. We hypothesize that different "strains" of fibrillar alpha-synuclein with different affinity/tropism, internalization and seeding properties, may account for the patho-physiological and clinical heterogeneity in Parkinson's disease and other synucleinopathies. We aim to determine a way to interfere with the binding to neurons of distinct alpha-synuclein assemblies and their prion-like propagation. To this end, we mapped the surface of three distinct alpha-synuclein strains. First, we implemented limited proteolysis and hydrogene-deuterium approaches combined to mass spectrometry in order to map, in vitro, the solvent exposed-surfaces of fibrillar alpha-synuclein assemblies generated in vitro. Second, we studied the processing of different alpha-synuclein strains using primary cultures of neurons and astrocytes in order to analyze the strain degradation characteristics in cellulo, related to the surface specificities determined in vitro. Mapping the surfaces of those assemblies and identification of exposed and protected strain-specific sequences open the way, in the long term, for developing highly specific binders that might either detect specific alpha-synuclein strains or inhibit cell-to-cell propagation disease progression

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Diaz, Gamboa Oscar Wilfredo. "Microencapsulação de tocoferóis em matrizes lipídicas advindas de gorduras low trans interesterificadas quimicamente". [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254680.

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Orientador: Lireny Aparecida Guaraldo Gonçalves
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-19T08:12:03Z (GMT). No. of bitstreams: 1 DiazGamboa_OscarWilfredo_D.pdf: 1876345 bytes, checksum: 56e9f8f4f7650f56a9f3dd8d60c68957 (MD5) Previous issue date: 2011
Resumo: O presente projeto visou estabelecer condições ideais de obtenção de um produto que poderá ser disponibolizado para comercialização no Brasil tendo como foco a encapsulação para aplicação na área alimentícia. Tocoferóis são antioxidantes naturais que podem ser utilizados para enriquecimento de alimentos. Contudo há a necessidade de proteção desse agente ativo por métodos especiais como a microencapsulação. No presente estudo foram desenvolvidos sistemas compostos por micropartículas obtidas por ¿spray chilling" utilizando lipídios interesterificados sem isômeros trans com óleo de soja totalmente hidrogenado na relação de 70:30% m/m respectivamente, com ponto de fusão na faixa de 40-65 °C para formação das matrizes. Alfa-tocoferol foi utilizado como principio ativo a ser encapsulado. Para a obtenção das micropartículas matrizes lipídicas foram fundidas e mantidas em banho à temperatura de 65 °C . O a-tocoferol foi adicionado nas misturas lipídicas que em seguida foram homogeinizados em ultraturrax. As soluções foram pulverizadas em atomizador duplo fluido aquecido também a 65 °C e pressão de ar de 0,25 MPa, com a a tomização efetuada dentro de uma câmara resfriada a 10 °C. Foi realizado um p lanejamento DCCR (Delineamento Central Rotacional) com 2 variáveis independentes: a velocidade de homogeneização (3000 a 11000 rpm) e a concentração de tocoferol (5-25 g/100g). A quantificação do princípio ativo encapsulado foi realizada utilizando técnica isocrática de cromatografia líquida de alta eficiência (CLAE). Os tratamentos foram caracterizados em relação à eficiência de encapsulação, morfologia, tamanho médio, estabilidade e liberação do princípio ativo. Para o estudo da estabilidade os tratamentos foram submetidos à estocagem por 180 dias em três diferentes temperaturas (ambiente 25°C ±5 °C, em estufa 22 °C e freezer a -18°C). Medidas de difração de raios-X (0 , 60, 120, 180 dias) e medidas calorimétricas (tempo zero) foram efetuadas. Foi realizada a incorporação das micropartículas em um produto comercial (Iogurte), que foi avaliado sensorialmente. De forma geral, as partículas lipídicas obtidas neste trabalho apresentaram bons resultados quanto à eficiência de encapsulação e apresentando forma esférica, com paredes contínuas, porém rugosas. Os termogramas, obtidos por calorimetria diferencial de varredura (DSC), em tempo zero, não apresentaram diferenças entre os ensaios. Os difratogramas foram muito semelhantes entre os tratamentos e constatou-se a presença de 3 picos principais que parecem estar associados à forma polimórfica ß. As micropartículas de liberação apresentaram boa capacidade de controle da liberação do composto ativo, mostrando-se potenciais para o uso futuro na indústria de alimentos. Finalmente os resultados da análise sensorial de aceitação não foram estatisticamente significativos para os atributos avaliados
Abstract: This project aimed to establish optimal conditions for obtaining a product that will be commercially available in Brazil, focusing on encapsulation for use in the food industry. Tocopherols are natural antioxidants that can be used for food enrichment.However, there is the need for protection of active agent by special methods, such as microencapsulation. The present study developed systems composed of microparticles obtained by "spray chilling" using an interesterified fat with no trans isomers with fully hydrogenated soybean oil in the ratio of 70:30% w/w respectively, with a melting point in the range of 40-65°C for the formation of matrices to encapsulate a-tocopherol as active principle.To obtain small particles a lipid matrices were melted in a water bath at a temperature of 65°C. The a-tocopherol was added to the lipid mixtures and then homogenized in Ultra Turrax for 5 min.The solutions were sprayed in double-fluid atomizer also heated to 65°C and air pressure of 0.25 MPa, the atomization performed inside a chamber cooled to 10°C. Were conducted a CCR design (Central Compo site Rotational Design) with two independent variables: the speed of homogenization (3000 to 11000 rpm) and the concentration of tocopherol (5-25 g/100 g).The quantification of the active ingredient encapsulated was performed using isocratic HPLC technique. The treatments were characterized with respect to encapsulation efficiency, morphology, average size and stability of the microparticles and release of active ingredient.For the stability study treatments were subjected to storage for 180 days at three different temperatures (ambient 25°C ± 5°C , 22°C in an oven and freezer -18°C).Since x-rays diffraction measurements (0, 60, 120, 180 days) and calorimetric measurements (time zero) were made. Were performed the incorporation of the microparticles in a commercial product (yogurt), which was evaluated using the sensory evaluation.In general, the lipid particles studied in this work showed good results in terms of encapsulation efficiency showing spherical shape, with solid rough walls. The thermograms obtained by DSC at time zero did not differ between trials.The XRD patterns were very similar among treatments and found the presence of three major peaks that are associated with the polymorphic form ß. The microparticles showed good ability to control the release of the active principle, showing potential for future use in the food industry. Finally the results of an smooth sensory acceptance indicated that the tested samples did not differ statistically from the standard sample for evaluated attributes
Doutorado
Tecnologia de Alimentos
Doutor em Tecnologia de Alimentos

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Mpako, Vuyolwethu Maxabiso Wessels. "Capture effects in spread-aloha packet protocols". Thesis, 2005. http://hdl.handle.net/10413/2824.

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Research in the field of random access protocols for narrow-band systems started as early as the 1970s with the introduction of the ALOHA protocol. From the research done in slotted narrow-band systems, it is well known that contention results in all the packets involved in the contention being unsuccessful. However, it has been shown that in the presence of unequal power levels, ore of the contending packets may be successful. Ibis is a phenomenon called capture. Packet capture has been shown to improve the performance of slotted narrow-band systems. Recently, much work has been done in the analysis of spread-spectrum ALOHA type code-division multiple access (CDMA) protocols. The issue of designing power control techniques to improve the performance of CDMA systems by reducing multiple access interference (MAl) has been a subject of much research. It has been shown that in the presence of power control schemes, the performance of spread-ALOHA CDMA systems is improved. However, it is also widely documented that the design of power control schemes capable of the ideal of compensation of radio propagation techniques is not possible for various reasons, and hence the imperfections in power control. None of the research known to the author has looked at capture in spread-ALOHA systems, and to a greater extent, looked at expressions for the performance of spreadALOHA systems in the presence of capture. In this thesis we introduce spread-ALOHA systems with capture as a manifestation of the imperfections in power control. We propose novel expressions for the computation of the perfonnance ofspread-ALOHA systems with capture.
Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, 2005.

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Achi, Hassan, University of Western Sydney, College of Health and Science e School of Engineering. "Performance analysis of single code spread ALOHA systems". 2006. http://handle.uws.edu.au:8081/1959.7/16703.

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Spread ALOHA has become one of the advanced multiple access techniques promising several advantages over existing conventional and spread spectrum based wireless systems. Spread ALOHA is currently recognised as a simplified wireless multiple access system which provides a higher bandwidth and may accommodate high number of users. This thesis investigates the employment of a unique spreading code in conjunction with Spread ALOHA as opposed to the common method of employing distinct spreading codes for all users on the communication channel. This feature of Spread ALOHA would eliminate the limitation on the number of users imposed by finding sufficient orthogonal spreading codes, and moreover it would simplify the system and reduce the receiver complexity. In this research I have investigated the state of the art on this topic, and I have modelled and simulated a Single Code Spread ALOHA system together with a conventional CDMA ALOHA system in order to analyse and compare the performance of both systems. This study has shown the viability of employing single code in Spread ALOHA systems, and hence eliminating what is considered a limiting factor in other systems such as CDMA. The performance of this proposed system is comparable with that of CDMA; however the selection of suitable PN codes is essential. The parametric study in this work was aimed to find optimum performance criteria for the Spread ALOHA system. all users on the spread spectrum system to have equal average; received power levels.
Master of Engineering (Hons)

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Libri sul tema "Spread ALOHA"

Turner, Olivia T. Spread for the Alpha. Independently Published, 2019.

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Aboumitri, Ioana. Spread Alofa: Nurturing Our World with Love. Independently Published, 2019.

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Harrison, Mark. Streptococci and staphylococci. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780198765875.003.0013.

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This chapter describes the microbiology of streptococci and staphylococci as it applies to Emergency Medicine, and in particular the Primary FRCEM examination. The chapter outlines the key details of the methods of spread and clinical features of Streptococcus pneumoniae, Streptococcus pyogenes, alpha-haemolytic streptococci, Staphylococcus aureus, MRSA, and Staphylococcus epidermidis. This chapter is laid out exactly following the RCEM syllabus, to allow easy reference and consolidation of learning.

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Cassidy, Jim, Donald Bissett, Roy A. J. Spence OBE, Miranda Payne, Gareth Morris-Stiff e Madhumita Bhattacharyya. Gynaecological cancers. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199689842.003.0020_update_001.

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Genitourinary cancers examines the malignancies arising in the kidney, ureter, bladder, prostate, testis, and penis. Renal cancer has high propensity for systemic spread, largely mediated by overexpression of vascular endothelial growth factor (VEGF). Treatments include surgery, immunotherapy, and targeted therapy. Wilms tumour, a childhood malignancy of the kidney, warrants specialist paediatric oncology management to provide expertise in its unique pathology, staging, and treatment, often with surgery and chemotherapy. Cancer of the bladder and ureters, another tobacco related cancer, may present as either superficial or invasive disease. The former is managed by transurethral resection and intravesical therapy. The latter may require radical surgery, preoperative chemotherapy, or radiotherapy. Prostate cancer, the commonest male cancer, is an androgen dependent malignancy. It has attracted controversy with regards to PSA screening, and potential over treatment with radical prostatectomy. Division into low, intermediate, and high risk disease according to tumour grade, stage, and PSA helps in deciding best treatment, antiandrogen therapy for metastatic disease, radiotherapy and adjuvant hormone therapy for locally advanced disease, either surgery or radiotherapy for early intermediate risk disease, and active monitoring for low risk cases. Testicular cancer divides according to pathology into seminoma, nonseminomatous germ cell tumours (NSGCT), and mixed tumours, the latter two frequently producing tumour markers, alpha-fetoprotein (AFP) and/or human chorionic gonadotrophin (HCG). Stage I disease is managed by inguinal orchidectomy and surveillance or adjuvant chemotherapy. More advanced disease is managed by chemotherapy, with high probability of cure in the majority. Penile cancer, often HPV related, can be excised when it presents early, but delay in presentation may lead to regional and systemic spread with poor prognosis.

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Visweswara Rao, Pasupuleti, Balam Satheesh Krishna e Mohammad Saffree Jeffree, a cura di. Coronaviruses Transmission, Frontliners, Nanotechnology and Economy. UMS Press, 2022. http://dx.doi.org/10.51200/coronavirusesdrraoums2021.

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Coronaviruses are the viruses which cause different types of diseases in humans and animals. They belong to Coronaviridae family. Coronaviruses have unique shape which consists of spiked rings and sometimes to deal with them is a tough task. They are the tiny organisms which can only be seen under the microscopes. Even though the corona viruses exist in nature since decades, however the seriousness is only seen with the pandemic SARS-CoV II or COVID-19. It has taken so many lives away and the loss of various businesses. Keeping in view these situations, the authors and editors try to bring few of the important aspects together and compiled this book. The transmissions occur through different means and the vaccines are under production by various giant companies. Second chapter deals with animals as sources of transmitting agents to spread corona virus. Up to date the Centre for Disease Control and Prevention (CDC) recognizes 7 species of coronaviruses that infect humans, with the earliest known species identified in the mid-1960s. The known human coronaviruses are 229E (alpha coronavirus), NL63 (alpha coronavirus), OC43 (beta coronavirus), HKU1 (beta coronavirus), MERS-CoV (causes Middle East Respiratory Syndrome, MERS), SARS-CoV (causes Severe Acute Respiratory Syndrome, SARS) and SARS-CoV-2 (causes the coronavirus disease also in 2019, also known as COVID-19). Third chapter dealt with risk assessment for front liners during COVID-19 pandemic and clearly explained about the risk assessment factors. Healthcare workers (HCWs) are on the frontline of treating patients infected with COVID-19. However, data related to its infection rate among HCWs are limited. Chapter 4 deals with the nanotechnology and its applications on viral diseases. Nanobiotechnology is science of nanoparticle synthesis by using biotechnological applications in biology, physics, engineering, drug delivery, diagnostics, and chemistry. The use of metal/ polymeric nanoparticles as drug delivery systems has become extensive in last two decades. The commercialization of developed novel nanoparticles/drug loaded polymeric nanoparticles delivery systems are required to eradicate virus with improved safety measures in the humans with affordable cost. Chapter 5 mainly focused on the impact of COVID -19 on China, Malaysia, Indonesia, and India. The outbreak of the Covid-19 pandemic is an unprecedented shock to the Emerging economies. The evidence reported in various studies indicates that epidemic disease impacts on a country's economy through several channels, including the health, transportation, agricultural and tourism sectors. In the chapter 6, the authors discussed the psychological response, ranges from adaptive to maladaptive spectrum. We wish to express our gratitude to all the authors and contributors from Malaysia, Indonesia, and India for readily accepting our invitation and timely contributions without any delay. We greatly appreciate their commitment. We also thank Universiti Malaysia Sabah and Universitas Abdurrab for the great collaboration and collaborative efforts.

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Frew, Anthony. Air pollution. A cura di Patrick Davey e David Sprigings. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199568741.003.0341.

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Any public debate about air pollution starts with the premise that air pollution cannot be good for you, so we should have less of it. However, it is much more difficult to determine how much is dangerous, and even more difficult to decide how much we are willing to pay for improvements in measured air pollution. Recent UK estimates suggest that fine particulate pollution causes about 6500 deaths per year, although it is not clear how many years of life are lost as a result. Some deaths may just be brought forward by a few days or weeks, while others may be truly premature. Globally, household pollution from cooking fuels may cause up to two million premature deaths per year in the developing world. The hazards of black smoke air pollution have been known since antiquity. The first descriptions of deaths caused by air pollution are those recorded after the eruption of Vesuvius in ad 79. In modern times, the infamous smogs of the early twentieth century in Belgium and London were clearly shown to trigger deaths in people with chronic bronchitis and heart disease. In mechanistic terms, black smoke and sulphur dioxide generated from industrial processes and domestic coal burning cause airway inflammation, exacerbation of chronic bronchitis, and consequent heart failure. Epidemiological analysis has confirmed that the deaths included both those who were likely to have died soon anyway and those who might well have survived for months or years if the pollution event had not occurred. Clean air legislation has dramatically reduced the levels of these traditional pollutants in the West, although these pollutants are still important in China, and smoke from solid cooking fuel continues to take a heavy toll amongst women in less developed parts of the world. New forms of air pollution have emerged, principally due to the increase in motor vehicle traffic since the 1950s. The combination of fine particulates and ground-level ozone causes ‘summer smogs’ which intensify over cities during summer periods of high barometric pressure. In Los Angeles and Mexico City, ozone concentrations commonly reach levels which are associated with adverse respiratory effects in normal and asthmatic subjects. Ozone directly affects the airways, causing reduced inspiratory capacity. This effect is more marked in patients with asthma and is clinically important, since epidemiological studies have found linear associations between ozone concentrations and admission rates for asthma and related respiratory diseases. Ozone induces an acute neutrophilic inflammatory response in both human and animal airways, together with release of chemokines (e.g. interleukin 8 and growth-related oncogene-alpha). Nitrogen oxides have less direct effect on human airways, but they increase the response to allergen challenge in patients with atopic asthma. Nitrogen oxide exposure also increases the risk of becoming ill after exposure to influenza. Alveolar macrophages are less able to inactivate influenza viruses and this leads to an increased probability of infection after experimental exposure to influenza. In the last two decades, major concerns have been raised about the effects of fine particulates. An association between fine particulate levels and cardiovascular and respiratory mortality and morbidity was first reported in 1993 and has since been confirmed in several other countries. Globally, about 90% of airborne particles are formed naturally, from sea spray, dust storms, volcanoes, and burning grass and forests. Human activity accounts for about 10% of aerosols (in terms of mass). This comes from transport, power stations, and various industrial processes. Diesel exhaust is the principal source of fine particulate pollution in Europe, while sea spray is the principal source in California, and agricultural activity is a major contributor in inland areas of the US. Dust storms are important sources in the Sahara, the Middle East, and parts of China. The mechanism of adverse health effects remains unclear but, unlike the case for ozone and nitrogen oxides, there is no safe threshold for the health effects of particulates. Since the 1990s, tax measures aimed at reducing greenhouse gas emissions have led to a rapid rise in the proportion of new cars with diesel engines. In the UK, this rose from 4% in 1990 to one-third of new cars in 2004 while, in France, over half of new vehicles have diesel engines. Diesel exhaust particles may increase the risk of sensitization to airborne allergens and cause airways inflammation both in vitro and in vivo. Extensive epidemiological work has confirmed that there is an association between increased exposure to environmental fine particulates and death from cardiovascular causes. Various mechanisms have been proposed: cardiac rhythm disturbance seems the most likely at present. It has also been proposed that high numbers of ultrafine particles may cause alveolar inflammation which then exacerbates preexisting cardiac and pulmonary disease. In support of this hypothesis, the metal content of ultrafine particles induces oxidative stress when alveolar macrophages are exposed to particles in vitro. While this is a plausible mechanism, in epidemiological studies it is difficult to separate the effects of ultrafine particles from those of other traffic-related pollutants.

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Capitoli di libri sul tema "Spread ALOHA"

Yang, Zhengwen, Qiang Wu, Yongqiang Lu, Pei Lu, Yinghong Hou e Manman Peng. "Enhanced ALOHA Algorithm for Chirp Spread Spectrum Positioning". In Pervasive Computing and the Networked World, 891–903. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-37015-1_79.

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Collard, Florian, Annamaria Recchia, Natalia Antip, Antonio Arcidiacono, Daniele Finocchiaro e Orazio Pulvirenti. "Performance Analysis of an Enhanced Spread Spectrum Aloha System". In Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, 26–34. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36787-8_4.

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Jibrail, Waseem, e Ranjith Liyana-Pathirana. "Packet Acquisition Evaluation of Slotted Spread ALOHA Data Networks". In Mobile and Wireless Communications, 217–24. Boston, MA: Springer US, 2003. http://dx.doi.org/10.1007/978-0-387-35618-1_26.

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Halliday, D. M. "Effects of Electrotonic Spread of EPSPs on Synaptic Transmission in Motoneurones: A Simulation Study". In Alpha and Gamma Motor Systems, 337–39. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4615-1935-5_73.

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Sharma, Poonam, Ashwani Kumar Dubey e Ayush Goyal. "Efficient Image Deblurring Using Alpha Plane Blending on Images Recovered with Linearly Varied Point Spread Function (PSF)". In Advances in Intelligent Systems and Computing, 509–22. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-5934-7_45.

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"Flocks of alpha-Cones". In Combinatorics of Spreads and Parallelisms, 287–300. CRC Press, 2010. http://dx.doi.org/10.1201/ebk1439819463-c20.

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Harrison, Dr Mark. "Streptococci and Staphylococci". In Revision Notes for MCEM Part A, 163–66. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199583836.003.0013.

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1.1 Streptococci, 163 1.2 Staphylococci, 165 • Gram positive cocci • Facultative anaerobes • Encapsulated, alpha haemolytic cocci • Methods of spread - ▪ Streptococcus pneumoniae is a common nasopharyngeal commensal ▪ Spread is by droplet ▪ Exogenous (respiratory droplet spread from carrier infecting another host) or endogenous (carrier develops impaired resistance to organism) infection may occur...

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Alinejad, Tahereh, Danial Zareh, Zuo Hao, Tengfei Zhou e Cheng-shui Chen. "SARS-CoV-2 Mutation Mechanism, Features, and Future Perspective". In Infectious Diseases. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.106905.

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Over two years, the SARS-CoV-2 virus has evolved by producing several variants by RNA polymerase mutation. This mutation created many virus variants that five of them are designated by WHO. These are Alpha, Beta, Gamma, Delta, and Omicron, among them Alpha, Delta, and Omicron spread faster. Coronaviruses (CoVs) are enveloped in positive-sense RNA viruses and contain huge RNA virus genomes. RNA polymerase controls the replication in which the genomic material is copied, and it often makes errors that lead to create a new mutation. Most mutations create a virus that cannot replicate and spread among people. However, some mutations lead to a virus that can replicate and create a variant. This chapter will discuss the mechanism of the mutations during the last two years and the future of these mutations in SARS-CoV-2.

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Hari, Riitta, e Aina Puce. "Brain Rhythms". In MEG-EEG Primer, a cura di Riitta Hari e Aina Puce, 165–88. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190497774.003.0010.

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This chapter provides examples of studies of MEG and EEG brain rhythms that have considerably increased understanding of the human brain’s sensory, motor, cognitive, and affective functions. Parieto-occipital alpha, Rolandic mu and auditory-cortex tau rhythms, as well as more widely spread beta, theta, gamma, delta and ultra-slow oscillations are described. Additionally, MEG/EEG signal changes that accompany different vigilance states, such as drowsiness and sleep, as well as anesthesia, are discussed. We emphasize the importance of timing information that MEG and EEG recordings, including the brain rhythms, provide. In this and subsequent chapters, we rely somewhat on our own studies and experiences, so as to give educational insights from the pitfalls and challenges we ourselves have experienced.

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Husam, Rajab, Ozoliņa Nadīna, Denysiuk Vladyslav e Gennart Gennart. "Hate speech toward youngsters in online media". In Proceedings of the first GiLE4Youth International Conference : The Development of Competencies for Employability, 42–49. GiLE Journal of Skills Development, 2021. http://dx.doi.org/10.56611/conf.proc.2021.1.42-49.

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The 21st century has come and is ahead of us, presenting fast changes in people's ways to interact while witnessing massive progress in media and communication. Generation Z, born in 1995, has by now become part of our societies' young workers force at a time when the internet was already well installed. Their progeny, the alpha generation (born after 2010), is part of an ultra-connected world, their parents have been documenting their lives from early birth. In 2020, when the mondial pandemia started spreading, it became a worldwide urge and need to communicate online. To confront the massive societal transformations, education may be getting late raising voices about these virtual relationships and interactions. How does hate speech appear and spread in these conditions? Where to set boundaries when the “ghost is in the wire” and may remain anonymous? Who should we turn to, who is responsible for social media? What are the consequences of mental health? Eventually, which solutions can we, youth workers, implement to support youngsters and prevent hate speech from raising? Those are the questions we wish to investigate.

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Atti di convegni sul tema "Spread ALOHA"

Hellany, A., e H. Achi. "Performance Analysis of Single Code Spread ALOHA Systems". In 2007 14th IEEE International Conference on Electronics, Circuits and Systems (ICECS '07). IEEE, 2007. http://dx.doi.org/10.1109/icecs.2007.4511067.

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Barnes, Vincent, e William Osborne. "Throughput performance of direct spread Slotted-Aloha packet networks". In 16th International Communications Satellite Systems Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1996. http://dx.doi.org/10.2514/6.1996-1114.

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Achi, H., A. Hellany e M. Nagrial. "Performance improvement of spread ALOHA systems using single code". In 2007 International Symposium on High Capacity Optical Networks and Enabling Technologies. IEEE, 2007. http://dx.doi.org/10.1109/honet.2007.4600268.

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Kota, Sastri, M. Vazquez-Castro e Jim Carlin. "Spread ALOHA Multiple Access for Broadband Satellite Return Channel". In 20th AIAA International Communication Satellite Systems Conference and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2002. http://dx.doi.org/10.2514/6.2002-1918.

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Huang, Yuqin, e Min Peng. "Congestion Perception Based on Load Estimation in Spread Spectrum Aloha". In 2020 IEEE 6th International Conference on Computer and Communications (ICCC). IEEE, 2020. http://dx.doi.org/10.1109/iccc51575.2020.9345282.

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HU, Xiuqi, Yubi QIAN, Huiling HOU, Siyue Sun, Guang LIANG e Shuai Han. "Chirp Spread Spectrum Aloha in LEO Satellite Internet of Things". In 2022 International Wireless Communications and Mobile Computing (IWCMC). IEEE, 2022. http://dx.doi.org/10.1109/iwcmc55113.2022.9824975.

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Xu Xingyao e Li Chengshu. "Performance of slotted ALOHA with spread spectrum and delay capture". In Proceedings of APCC/OECC'99 - 5th Asia Pacific Conference on Communications/4th Optoelectronics and Communications Conference. IEEE, 1999. http://dx.doi.org/10.1109/apcc.1999.824933.

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Ripplinger, David. "Backoff mechanisms in narrow band and spread spectrum aloha networks". In the first ACM MobiHoc workshop. New York, New York, USA: ACM Press, 2012. http://dx.doi.org/10.1145/2248326.2248330.

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Ogose, Y., T. Arai, H. Inai e H. Habuchi. "A Study of the Three-Valued CSK Spread ALOHA System". In 6th Asia-Pacific Symposium on Information and Telecommunication Techniques. IEEE, 2005. http://dx.doi.org/10.1109/apsitt.2005.203672.

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Xiao, Zhenyu, Wentao Chen, Depeng Jin e Lieguang Zeng. "Spread ALOHA based random access scheme for macro cell CDMA systems". In 2008 11th IEEE Singapore International Conference on Communication Systems (ICCS). IEEE, 2008. http://dx.doi.org/10.1109/iccs.2008.4737357.

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Rapporti di organizzazioni sul tema "Spread ALOHA"

Citovsky, Vitaly, e Yedidya Gafni. Viral and Host Cell Determinants of Nuclear Import and Export of the Tomato Yellow Leaf Curl Virus in Tomato Plants. United States Department of Agriculture, agosto 2002. http://dx.doi.org/10.32747/2002.7585200.bard.

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Tomato yellow leaf curl geminivirus (TYLCV) is a major pathogen of cultivated tomato, causing up to 100% crop loss in many parts of the world. In Israel, where TYLCV epidemics have been recorded since the 1960' s, this viral disease is well known and has been of economic significance ever since. In recent years, TYLCV outbreaks also occurred in the "New World" - Cuba, The Dominican Republic, and in the USA, in Florida, Georgia and Louisiana. Thus, TYLCV substantially hinders tomato growth throughout the world. Surprisingly, however, little is known about the molecular mechanisms of TYLCV interaction with the host tomato cells. The present proposal, a continuation of the project supported by BARD from 1994, expanded our understanding of the molecular mechanisms by which TYLCV enters the host cell nucleus for replication and transcription and exits it for the subsequent cell-to-cell spread. Our project sought two objectives: I. To study the roles of the viral capsid protein (CP) and host cell factors in TYLCV nuclear import. II. To study the roles of CP and host cell factors in TYLCV nuclear export. Our research toward these goals have produced the following major achievements: . Developed a one-hybrid assay for protein nuclear export and import (#3 in the List of Publications). . Identified a functional nuclear export signal (NES) in the capsid protein (CP) of TYLCV (#3 in the List of Publications). . Discovered homotypic interactions between intact TYLCV CP molecules and analyzed these interactions using deletion mutagenesis of TYLCV CP (#5 in the List of Publications). . Showed developmental and tissue-specific expression of the host factor required for nuclear import of TYLCV CP, tomato karyopherin alpha 1, in transgenic tomato plants (#14 in the List of Publications). . By analogy to nuclear import of TYLCV ,identified an Arabidopsis VIPI protein that participates in nuclear import of Agrobacterium T -complexes via the karyopherin alpha pathway (#4,6, and 8 in the List of Publications). These research findings provided significant insights into (i) the molecular pathway of TYLCV entry into the host cell nucleus, and (ii) the mechanism by which TYLCV is exported from the nucleus for the cell-to-cell spread of infection. Furthermore, the obtained knowledge will help to develop specific strategies to attenuate TYLCV infection, for example, by blocking viral entry into and/or exit out of the host cell nucleus. Also, as much of our findings is relevant to all geminiviruses, new anti- TYLCV approaches developed based on the results of our research will be useful to combat other members of the Geminivirus family. Finally, in addition to the study of TYLCV nuclear import and export, our research contributed to our understanding of general mechanisms for nucleocytoplasmic shuttling of proteins and nucleic acids in plant cells.

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