279 resultados para Modulation (Music)
Resumo:
A very high-quality sub-band ADPCM music coding scheme which compresses high-fidelity music signals, bandlimited to 15kHz, to an equivalent PCM representation of only 4 bits per sample, is described. By processing music sampled at 32 kHz, this coder exhibits a total bit rate of only 128kbit/s and is consequently applicable to the ISDN. Subjective tests conducted with this coder have shown that music recovered from the compression scheme is essentially indistinguishable from the original material. The results obtained are of major importance, not only for ISDN and broadcasting, but also for other digital audio technology such as compact disc (CD) and digital audio tape.
Resumo:
The subjective performance of the G. 722 7-kHz wideband speech coding recommendation using music signals is described. A number of audible distortions specific to music signals were found to be present in real-time evaluations of the coder. As a result, three modifications are proposed which are found to improve the performance for music signals. These modifications are compatible with the G. 722 system configuration. Modifications made to G. 722 to alleviate the most serious aspects of the noise modulation are described: (1) an adaptive bit allocation scheme is used to reduce short and long-term nonoptimality; (2) spectral noise shaping is incorporated, significantly enhancing the subjective performance of certain modes; and (3) backward block adaptive prediction is used.
Resumo:
Power back-off performances of a new variant power-combining Class-E amplifier under different amplitude-modulation schemes such as continuous wave (CW), envelope elimination and restoration (EER), envelope tracking (ET) and outphasing are for the first time investigated in this study. Finite DC-feed inductances rather than massive RF chokes as used in the classic single-ended Class-E power amplifier (PA) resulted from the approximate yet effective frequency-domain circuit analysis provide the wherewithal to increase modulation bandwidth up to 80% higher than the classic single-ended Class-E PA. This increased modulation bandwidth is required for the linearity improvement in the EER/ET transmitters. The modified output load network of the power-combining Class-E amplifier adopting three-harmonic terminations technique relaxes the design specifications for the additional filtering block typically required at the output stage of the transmitter chain. Qualitative agreements between simulation and measurement results for all four schemes were achieved where the ET technique was proven superior to the other schemes. When the PA is used within the ET scheme, an increase of average drain efficiency of as high as 40% with respect to the CW excitation was obtained for a multi-carrier input signal with 12 dB peak-to-average power ratio. © 2011 The Institution of Engineering and Technology.
Resumo:
The effect of restructuring the form of three unfamiliar pop/rock songs was investigated in two experiments. In the first experiment, listeners' judgements of the likely location of sections of novel popular songs were explored by requiring participants to place the eight sections (Intro - Verse 1 - Chorus 1 - Verse 2 - Chorus 2 - Bridge (solo) - Chorus 3 - Extro) of the songs into the locations they thought them most likely to occur within the song. Results revealed that participants were able to place the sections in approximately the right location with some accuracy, though they were unable to differentiate between choruses. In Experiment 2, three versions of each of the songs were presented in three different structures: intact (original form), medium restructured (the sections in a moderately changed order), and highly restructured (more severe restructuring). The results show that listeners' judgments of predictability and liking were largely uninfluenced by the restructuring of the songs, in line with findings for classical music. Moment-by-moment liking judgements of the songs demonstrated a change in liking judgements with repeated exposure, though the trend was downwards with repeated exposure rather than upwards. Detailed analysis of moment-by-moment judgements at the ends and beginnings of sections showed that listeners were able to respond quickly to intact songs, but not to restructured songs. The results suggest that concatenism prevails in listening to popular song at the expense of paying attention to larger structural features. © 2012 by the regents of the university of california all rights reserved.
Resumo:
Staged as an attempt to ‘bring together Shakespeare’s plays and Tang Xian Zu’s classical Kunqu opera, The Peony Pavilion,’ (Ong, Programme Notes) Awaking stands as Singapore Director Ong Keng Sen’s most recent and prominent attempt at engaging issues of the intercultural through music and sound. While Ong’s previous intercultural projects sought to explore the politics of intercultural performance through the exchange, layering, confrontation and inter-mixing of Asian performance modes as visual aesthetics, Awaking is a performance at the borders of theatrical and musical conventions, as it features the music and musicians as central performative devices of staging the intercultural. Northern Kunqu opera, Chinese classical music and Elizabethan folk tunes from Shakespeare’s plays were re-moved, re-contextualised, and juxtaposed to explore ‘differing yet connected philosophies on love, death, and the afterlife’ (Awaking, Publicity). These humanist and ‘universal’ themes found expression in the ‘universal’ language of music. Through a study of the musicalities and sonic expressions of Awaking, the paper seeks to explore the implications of such cultural-musical juxtapositions. The paper engages, specifically, with the problematics and possibilities of music as a ‘universal language’ as implied by Ong’s concordance of Eastern and Western sounds in the final act. It further considers the politics of an intercultural soundscape and the acoustemologies of such an intercultural approach.
Resumo:
This paper considers the musicological aspects of the songs performed by Ophelia in Shakespeare's Hamlet. It proposes a reconsideration of the concept of madness and insanity by an attentive, attuned and learned listening to the songs sung by Ophelia and the ways in which they are performed and received.
Resumo:
This paper considers the integral aspect of music as performed in Shakespeare's Twelfth Night. It posits that music is that which orders and structures time in its interplay throughout the play.
Resumo:
Music has always been used as an important dramaturgical strategy in Western theatre to create a holistic theatrical experience. In Shakespeare’s plays, music was employed as a unique dramaturgical device for various purposes. Twelfth Night distinguishes itself from among the many plays that employ music because it begins, ends and progresses with music. Music pervades Twelfth Night and is tightly interwoven into the thematic concerns of the play such as love and gender. Because of music’s elusive nature and the difficulty of discussing a musical aesthetics, Shakespearean music critics have approached music in the play as a theme or an idea. This paper hopes to develop upon older scholarship by introducing an alternate framework of considering music’s musicality through a musicological analysis of the songs in Twelfth Night. In so doing, the paper hopes to show how and why music can modulate our responses to the play and in particular, to the theme of gender, a problematic issue that produces the elusive and darker nature of this festive comedy.
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Aflatoxin B1 (AFB1), a mycotoxin produced by Aspergillus flavus or A. parasiticus, is a frequent contaminant of food and feed. This toxin is hepatotoxic and immunotoxic. The present study analyzed in pigs the influence of AFB1 on humoral and cellular responses, and investigated whether the immunomodulation observed is produced through interference with cytokine expression. For 28 days, pigs were fed a control diet or a diet contaminated with 385, 867 or 1807 mu g pure AFB1/kg feed. At days 4 and 15, pigs were vaccinated with ovalbumin. AFB1 exposure, confirmed by an observed dose-response in blood aflatoxin-albumin adduct, had no major effect on humoral immunity as measured by plasma concentrations of total IgA, IgG and IgM and of anti-ovalbumin IgG. Toxin exposure did not impair the mitogenic response of lymphocytes but delayed and decreased their specific proliferation in response to the vaccine antigen, suggesting impaired lymphocyte activation in pigs exposed to AFB1. The expression level of pro-inflammatory (TNF-alpha, IL-1 beta, IL-6, IFN-gamma) and regulatory (IL-10) cytokines was assessed by real-time PCR in spleen. A significant up-regulation of all 5 cytokines was observed in spleen from pigs exposed to the highest dose of AFB1. In pigs exposed to the medium dose, IL-6 expression was increased and a trend towards increased IFN-gamma and IL-10 was observed. In addition we demonstrate that IL-6 impaired in vitro the antigenic- but not the mitogenic-induced proliferation of lymphocytes from control pigs vaccinated with ovalbumin. These results indicate that AFB1 dietary exposure decreases cell-mediated immunity while inducing an inflammatory response. These impairments in the immune response could participate in failure of vaccination protocols and increased susceptibility to infections described in pigs exposed to AFB1. (C) 2008 Elsevier Inc. All rights reserved.
Resumo:
Rationale: Histone deacetylase (HDAC)7 is expressed in the early stages of embryonic development and may play a role in endothelial function.
Objective: This study aimed to investigate the role of HDAC7 in endothelial cell (EC) proliferation and growth and the underlying mechanism.
Methods and Results: Overexpression of HDAC7 by adenoviral gene transfer suppressed human umbilical vein endothelial cell (HUVEC) proliferation by preventing nuclear translocation of ß-catenin and downregulation of T-cell factor-1/Id2 (inhibitor of DNA binding 2) and cyclin D1, leading to G1 phase elongation. Further assays with the TOPFLASH reporter and quantitative RT-PCR for other ß-catenin target genes such as Axin2 confirmed that overexpression of HDAC7 decreased ß-catenin activity. Knockdown of HDAC7 by lentiviral short hairpin RNA transfer induced ß-catenin nuclear translocation but downregulated cyclin D1, cyclin E1 and E2F2, causing HUVEC hypertrophy. Immunoprecipitation assay and mass spectrometry analysis revealed that HDAC7 directly binds to ß-catenin and forms a complex with 14-3-3 e, ?, and ? proteins. Vascular endothelial growth factor treatment induced HDAC7 degradation via PLC?-IP3K (phospholipase C?–inositol-1,4,5-trisphosphate kinase) signal pathway and partially rescued HDAC7-mediated suppression of proliferation. Moreover, vascular endothelial growth factor stimulation suppressed the binding of HDAC7 with ß-catenin, disrupting the complex and releasing ß-catenin to translocate into the nucleus.
Conclusions: These findings demonstrate that HDAC7 interacts with ß-catenin keeping ECs in a low proliferation stage and provides a novel insight into the mechanism of HDAC7-mediated signal pathways leading to endothelial growth
Resumo:
Sex steroids contribute to modulate GH secretion in man. However, both the exact locus and mechanism by which their actions are exerted still remain not clearly understood. We undertook a number of studies designed to ascertain: (1) whether or not sudden or chronic changes in circulating gonadal steroids may affect GH secretion in normal adults; and (2) the reason(s) for gender-related dimorphic pattern of GH release. The pituitary reserve of GH, as evaluated by means of a GHRH challenge, was similar in women with anorexia nervosa and in normally menstruating women. Estrogenic receptor blockade with tamoxifen (TMX) did not significantly change GHRH-induced GH response in these normal women. Therefore, acute or chronic hypoestrogenism apparently had no important effects at level of somatotrophs. In another group of normal women we tested the possibility that changes in circulating estrogens might induce changes in the hypothalamic-somatotroph rhythm (HSR). GHRH challenges were performed throughout a menstrual cycle, and again after having achieved functional ovarian blockade with a GnRH agonist treatment. Short-term ovarian blockade did not significantly affect the parameters of GH response to GHRH, although it was accompanied by an increase in the number of women ina refractory HSR phase at testing. This suggested a low potentiating effect on the basic pattern of somatostatin (SS) release occurring as a consequence of the decrease in circulating estrogens. In normal men, neither the GH response to GHRH nor the HSR were affected by functional testicular blockade (after GnRH agonist treatment). However, the administration of testosterone enanthate (250 mg) to another group of men increased both the GHRH-induced GH release and the number of subjects in a spontaneous secretory HSR phase at testing; these were reversed by estrogenic receptor blockade with TMS. In another group of normal men, the fraction of GH secreted in pulses (FGHP) during a nocturnal sampling period was significantly decreased by testicular blockade. Other parameters of GH secretion, such as the number of GH pulses and their mean amplitude (A), and the mean plasma GH concentration (MCGH), showed a slight, although not significant, decrease following the lack of androgens. The administration of testosterone enanthate (500 mg) reversed these parameters to values similar to those in the basal study. Interestingly, when tamoxifen was given after testosterone enanthate, A, MCGH and FGHP increased to values significantly higher than in any other experimental condition in that study. In all, these data suggest that 17ß-estradiol may participate in GH modulation by inhibiting the hypothalamic release of somatostatin, while testosterone stimulates it. The results obtained after estrogenic receptor blockade appear to indicate that the effect of testosterone in such a modulation is dependent on its aromatization to 17ß-estradiol. The differential levels of this steroid in both sexes might account for the sexual dimorphic pattern of GH secretion. From other data in the literature, obtained in rats, and our preliminary data in children with constitutional delay of growth and puberty, it is tempting to speculate that the effect of 17ß-estradiol may be exerted by modifying the functional activity of a-2 adrenergic pathways involved in the negative modulation of SS release.
Resumo:
This article documents the creation of a work by the authors based on a score written by the composer John Cage entitled 'Owenvarragh: A Belfast Circus on The Star Factory.' The article is part of a documentary portfolio in the journal which also includes a volume of the poetry created by Dowling in accordance with the instructions of the Cage score, and a series of documentary videos on the creation of the work and its first performance. Cage's score is based on his work 'Roaratorio: An Irish Circus on Finnegan's Wake' (1979) and it provides a set of detailed instructions for the musical realisation of a literary work. The article documents this first fully realised version of the score since Cage first produced 'Roaratorio' in 1979. The work, which was motivated by the Cage centenary year in 2012, musically realises Carson's book 'The Star Factory' (1998), a novelestic autobiography of Carson's Belfast childhood. The score required the creation of a fixed media piece based on over 300 field recordings of the sounds and places mentioned in the book, a volume of poetry created from the book which is recited to form the rhythmic spine of the work, and the arrangement of a performance including these two components along with live musical performance by the authors in collaboration with three other musicians under their direction, and a video installation created for the work. The piece has been performed three times: in association with the Sonorities 2012 Festival at Queen's University of Belfast (March 2012), at The Belfast Festival at Queen's (October 2012), and in the Rymer Auditoium of the University of York (June 2013).
Additional information:
The work which the article documents was conceived by Monaghan and Dowling, and the project was initiated by Monaghan after a she received a student prize to support its development and first performance. Elements of the project will be included in her PhD dissertation for which Dowling is a supervisor. Monaghan created the fixed media piece based on over 300 field recordings, the largest single aspect of realising Cage's score. Dowling was responsible for initiating the collaboration with Ciaran Carson, and for two other components: the creation of a volume of poetry derived from the literary work which is recited in the performance, and the creation of and supervision of the technical work on a video which accompanies the piece. The co-authors consulted closely during the work on these large components from May 2011 until March 2012 when the first performance took place. The co-authors also shared in numerous other artistic and organisational aspects of the production, including the arrangement and performnance of the music, musical direction to other performers, and marketing.
Resumo:
Gelsolin is a cytoskeletal protein which participates in actin filament dynamics and promotes cell motility and plasticity. Although initially regarded as a tumor suppressor, gelsolin expression in certain tumors correlates with poor prognosis and therapy-resistance. In vitro, gelsolin has anti-apoptotic and pro-migratory functions and is critical for invasion of some types of tumor cells. We found that gelsolin was highly expressed at tumor borders infiltrating into adjacent liver tissues, as examined by immunohistochemistry. Although gelsolin contributes to lamellipodia formation in migrating cells, the mechanisms by which it induces tumor invasion are unclear. Gelsolin's influence on the invasive activity of colorectal cancer cells was investigated using overexpression and small interfering RNA knockdown. We show that gelsolin is required for invasion of colorectal cancer cells through matrigel. Microarray analysis and quantitative PCR indicate that gelsolin overexpression induces the upregulation of invasion-promoting genes in colorectal cancer cells, including the matrix-degrading urokinase-type plasminogen activator (uPA). Conversely, gelsolin knockdown reduces uPA levels, as well as uPA secretion. The enhanced invasiveness of gelsolin-overexpressing cells was attenuated by treatment with function-blocking antibodies to either uPA or its receptor uPAR, indicating that uPA/uPAR activity is crucial for gelsolin-dependent invasion. In summary, our data reveals novel functions of gelsolin in colorectal tumor cell invasion through its modulation of the uPA/uPAR cascade, with potentially important roles in colorectal tumor dissemination to metastatic sites.
Resumo:
Conventional approaches of digital modulation schemes make use of amplitude, frequency and/or phase as modulation characteristic to transmit data. In this paper, we exploit circular polarization (CP) of the propagating electromagnetic carrier as modulation attribute which is a novel concept in digital communications. The requirement of antenna alignment to maximize received power is eliminated for CP signals and these are not affected by linearly polarized jamming signals. The work presents the concept of Circular Polarization Modulation for 2, 4 and 8 states of carrier and refers them as binary circular polarization modulation (BCPM), quaternary circular polarization modulation (QCPM) and 8-state circular polarization modulation (8CPM) respectively. Issues of modulation, demodulation, 3D symbol constellations and 3D propagating waveforms for the proposed modulation schemes are presented and analyzed in the presence of channel effects, and they are shown to have the same bit error performance in the presence of AWGN compared with conventional schemes while provide 3dB gain in the flat Rayleigh fading channel.