57,808 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
<i>Rubus tetsunii</i>, a replacement name for the Chinese <i>R. lobatus</i> T. T. Yu & L. T. Lu (Rosaceae)
No full textWANG, HUANCHONG, SUN, HANG (2013): Rubus tetsunii, a replacement name for the Chinese R. lobatus T. T. Yu & L. T. Lu (Rosaceae). Phytotaxa 79 (2): 63-64, DOI: 10.11646/phytotaxa.79.2.3, URL: http://dx.doi.org/10.11646/phytotaxa.79.2.
POLAR investigation of the Sun—POLARIS
No full textThe POLAR Investigation of the Sun (POLARIS) mission uses a combination of a gravity assist and solar sail propulsion to place a spacecraft in a 0.48 AU circular orbit around the Sun with an inclination of 75° with respect to solar equator. This challenging orbit is made possible by the challenging development of solar sail propulsion. This first extended view of the high-latitude regions of the Sun will enable crucial observations not possible from the ecliptic viewpoint or from Solar Orbiter. While Solar Orbiter would give the first glimpse of the high latitude magnetic field and flows to probe the solar dynamo, it does not have sufficient viewing of the polar regions to achieve POLARIS’s primary objective: determining the relation between the magnetism and dynamics of the Sun’s polar regions and the solar cycle
DNA fusion gene vaccination mobilizes effective anti-leukemic cytotoxic T lymphocytes from a tolerized repertoire
No full textThe majority of known human tumor-associated antigens derive from non-mutated self proteins. T cell tolerance, essential to prevent autoimmunity, must therefore be cautiously circumvented to generate cytotoxic T cell responses against these targets. Our strategy uses DNA fusion vaccines to activate high levels of peptide-specific CTL. Key foreign sequences from tetanus toxin activate tolerance-breaking CD4+ T cell help. Candidate MHC class Ibinding tumor peptide sequences are fused to the C terminus for optimal processing and presentation. To model performance against a leukemia-associated antigen in a tolerized setting, we constructed a fusion vaccine encoding an immunodominant CTL epitopederived from Friend murine leukemia virus gag protein (FMuLVgag) and vaccinated tolerant FMuLVgag-transgenic (gag-Tg) mice. Vaccination with the construct induced epitopespecificIFN-c-producing CD8+ T cells in normal and gag-Tg mice. The frequency and avidity of activated cells were reduced in gag-Tg mice, and no autoimmune injury resulted. However, these CD8+ T cells did exhibit gag-specific cytotoxicity in vitro and in vivo. Also, epitope-specific CTL killed FBL-3 leukemia cells expressing endogenous FMuLVgag antigen and protected against leukemia challenge in vivo. These results demonstrate a simple strategy to engage anti-microbial T cell help to activate epitope-specific polyclonal CD8+ T cell responses from a residual tolerized repertoire
SunSmart? Skin cancer knowledge and preventive behaviour in a British population representative sample
No full textThe incidence of skin cancer has risen rapidly in the UK over the last 20 years, prompting public health organizations to try and raise awareness of the dangers of sun exposure and the need to practice sun-safe behaviour. This study aimed to assess baseline levels of sun-safe knowledge and behaviour in a British population-representative sample, prior to the launch of Cancer Research UK's 'SunSmart' campaign. A face-to-face survey was conducted through the Office for National Statistics as part of their Omnibus survey. In total, 1848 men and women aged 18 and over were interviewed. Knowledge of what to do to reduce skin cancer risk was modest. Two-thirds mentioned avoiding the sun by seeking shade, 50% mentioned covering up and only 43% said to use high factor sunscreen. Practice of sun-safe behaviours was also poor, with only one-third saying they sought shade, covered up or used high factor sunscreen to protect themselves from the sun. Men and those from lower socioeconomic groups were least informed and least likely to report using sun-protective behaviours. Increases in both knowledge and use of appropriate sun-protective behaviours are needed if skin cancer incidence rates are to decrease
Extension of the sun-synchronous Orbit
No full textThrough careful consideration of the orbit perturbation force due to the oblate nature of the primary body a secular variation of the ascending node angle of a near-polar orbit can be induced without expulsion of propellant. Resultantly, the orbit perturbations can be used to maintain the orbit plane in, for example, a near-perpendicular (or at any other angle) alignment to the Sun-line throughout the full year of the primary body; such orbits are normally termed Sun-synchronous orbits [1, 2]. Sun-synchronous orbits about the Earth are typically near-circular Low-Earth Orbits (LEOs), with an altitude of less than 1500 km. It is normal to design a LEO such that the orbit period is synchronised with the rotation of the Earth‟s surface over a given period, such that a repeating ground-track is established. A repeating ground-track, together with the near-constant illumination conditions of the ground-track when observed from a Sun-synchronous orbit, enables repeat observations of a target over an extended period under similar illumination conditions [1, 2]. For this reason, Sun-synchronous orbits are extensively used by Earth Observation (EO) platforms, including currently the Environmental Satellite (ENVISAT), the second European Remote Sensing satellite (ERS-2) and many more. By definition, a given Sun-synchronous orbit is a finite resource similar to a geostationary orbit. A typical characterising parameter of a Sun-synchronous orbit is the Mean Local Solar Time (MLST) at descending node, with a value of 1030 hours typical. Note that ERS-1 and ERS-2 used a MLST at descending node of 1030 hours ± 5 minutes, while ENVISAT uses a 1000 hours ± 5 minutes MLST at descending node [3]. Following selection of the MLST at descending node and for a given desired repeat ground-track, the orbit period and hence the semi-major axis are fixed, thereafter assuming a circular orbit is desired it is found that only a single orbit inclination will enable a Sun-synchronous orbit [2]. As such, only a few spacecraft can populate a given repeat ground-track Sun-synchronous orbit without compromise, for example on the MLST at descending node. Indeed a notable feature of on-going studies by the ENVISAT Post launch Support Office is the desire to ensure sufficient propellant remains at end-of-mission for re-orbiting to a graveyard orbit to ensure the orbital slot is available for future missions [4]. An extension to the Sun-synchronous orbit is considered using an undefined, non-orientation constrained, low-thrust propulsion system. Initially the low-thrust propulsion system will be considered for the free selection of orbit inclination and altitude while maintaining the Sun-synchronous condition. Subsequently the maintenance of a given Sun-synchronous repeat-ground track will be considered, using the low-thrust propulsion system to enable the free selection of orbit altitude. An analytical expression will be developed to describe these extensions prior to then validating the analytical expressions within a numerical simulation of a spacecraft orbit. Finally, an analysis will be presented on transfer and injection trajectories to these orbits
MAGEC_2024
No full textMAGEC (Magma And Gas Equilibrium Calculator)
Author: Chenguang Sun
Copyright, 2025
This Matlab program calculates the equilibrium distribution of C-H-O-S volatiles (H2, H2O, CO, CO2, CH4, H2S, SO2, S2, COS, O2) in gas-melt coupled systems.
Updates on April 27, 2025:
1. Added additional options for CO2 and H2O solubility models
2. Corrected CO solubility models
If you use this program for your publications, please cite the following references:
1. Sun, C. and Yao, L., 2024. Redox equilibria of iron in low-to high-silica melts: A simple model and its applications to CHOS degassing. Earth and Planetary Science Letters, 638, p.118742. [Note: This is the reference for MAGEC_2024 with new Fe- and S-redox models and flexible setting options.]
2. Sun, C. and Lee, C.T.A., 2022. Redox evolution of crystallizing magmas with CHOS volatiles and its implications for atmospheric oxygenation. Geochimica et Cosmochimica Acta, 338, pp.302-321. [Note: This is the reference for the first version of MAGEC.]
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How to run the program:
1. Input T/P/logfO2 (or Fe3+/FeT) and compositions in the input file (.xlsx).
Make sure you use different names for the input and output files.
The batch data could be polybaric/isobaric/adiabatic degassing.
2. Modify the "settings" in the input file.
3. Open [Run_MAGEC_2024_v2.m] in Matlab
4. Go to [Editor] Tab in Matlab and click [Run] button.
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Perspectives on Identity, Migration, and Displacement
No full textPerspectives on Identity, Migration, and Displacement -- edited by Steven Tötösy de Zepetnek, I-Chun Wang, and Hsiao-Yu Sun (Kaohsiung: National Sun Yat-sen University Press, 2010. ISBN 9789860235418 209 pages, bibliography, index) is a collection of articles about sociological and literary aspects of identity formation as a consequence of (im)migration. (Im)migration results in the problematics of assimilation and hybridity and in postcolonial scholarship, in particular, attention is paid to the concept of migration termed Creolization on the ground that cultural contact, cultural transmission, and cultural transformation result in the creation of new cultures. Copyright release by National Sun Yat-sen University to the authors 2013
Research update: Progress in synthesis of nanoparticle dimers by self-assembly
No full textThis article highlights recent advances in the controlled self-assembly of nanoparticles to produce dimeric nanoparticle structures. The relevance of this emergent field is discussed in terms of recent applications in plasmonics and chemical catalysis. The concept of bond-valence applied to nanoparticles will be discussed, emphasizing some general approaches that have been successfully used to build these structures. Further, the asymmetric functionalization of nanoparticles surfaces as a path to drive selective aggregation, the use of biomolecules to self-assemble nanoparticles into dimers in solution, and the confinement of aggregates in small cavities are discussed. © 2014 Author(s)
A grounded theory of female adolescent behaviour in the sun: comfort matters.
No full textThe aim of the research was to generate a grounded theory to explain the behaviour of young women in the sun. The study sought to explore the sun-related experiences of
young women in order to gain new insights into the influences upon them. The study was qualitative by design and utilised grounded theory method as developed by Glaser.
Twenty female participants, aged 14 to 17 years old were included in the study. They formed six groups. Thirteen interviews were carried out with the groups and six one-to one interviews took place with individuals. All interviews were semi-structured and were based upon the participants' experiences of being in the sun. Data was analysed using the
constant comparative method of data analysis, concordant with Glaserian grounded theory method. Five explanatory categories emerged from the data; Fitting In, Being Myself,
Being Physically Comfortable, Slipping Up and a core category of Being Comfortable. One of the issues that emerged was that some young women believed their social
acceptance depended on their appearance and they conformed to this end. The theory, derived from the categories, proposes that when in the sun, young women direct their
activities toward meeting physical and psychosocial comfort needs. Comfort matters to them because it has implications for their wellbeing. This thesis contributes to the literature about the behaviours of young women in the sun.
By increasing understanding of the factors that influence them, it also adds to the body of knowledge related to the primary prevention of skin cancer with teenage girls in the United Kingdom. The outcome of the research and its contribution to knowledge is a grounded theory, which explains the basis of the behaviours of young women in the sun. It appears that no other study has explored the experiences of UK adolescent females specifically, in
a qualitative way and with the intention of producing a theory to explain them
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