836 research outputs found

    Application of SDMA with scheduling for MIMO MC-CDMA

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    Incoming Beyond 3G systems provides high data rates by using several techniques including Beamforming. Convenient DRA design is required to optimize the capabilities offered by smart antennas. This paper is to presents a DRA algorithm based on the HSDPA of UMTS, including scheduling that exploit SDMA technique that was implemented in the ambit of the IST 4MORE project. Results shown cell throughput gain of SDMA compared to sectorized cells about 76%, and that SDMA gain will increase with user diversity within the cell

    Facing the wind of the pre-FUor V1331 Cyg

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    The mass outflows in T Tauri stars (TTS) are thought to be an effective mechanism to remove angular momentum during the pre-main-sequence contraction of a low-mass star. The most powerful winds are observed at the FUor stage of stellar evolution. V1331 Cyg has been considered as a TTS at the pre-FUor stage. We analyse high-resolution spectra of V1331 Cyg collected in 1998-2007 and 20-d series of spectra taken in 2012. For the first time the photospheric spectrum of the star is detected and stellar parameters are derived: spectral type G7-K0 IV, mass 2.8 Msun, radius 5 Rsun, vsini < 6 km/s. The photospheric spectrum is highly veiled, but the amount of veiling is not the same in different spectral lines, being lower in weak transitions and much higher in strong transitions. The Fe II 5018, Mg I 5183, K I 7699 and some other lines of metals are accompanied by a `shell' absorption at radial velocity of about -240 km/s. We show that these absorptions form in the post-shock gas in the jet, i.e. the star is seen though its jet. The P Cyg profiles of H-alpha and H-beta indicate the terminal wind velocity of about 500 km/s, which vary on time-scales from several days to years. A model of the stellar wind is developed to interpret the observations. The model is based on calculation of hydrogen spectral lines using the radiative transfer code TORUS. The observed H-alpha and H-beta line profiles and their variability can be well reproduced with a stellar wind model, where the mass-loss rate and collimation (opening angle) of the wind are variable. The changes of the opening angle may be induced by small variability in magetization of the inner disc wind. The mass-loss rate is found to vary within (6-11)x10^{-8} Msun/yr, with the accretion rate of 2.0x10^{-6} Msun/yr.Comment: 11 pages, 12 figures; accepted for publication in MNRAS. Typographical errors have been corrected after the proof stag

    Dermatoses Específicas da Gravidez

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    During pregnancy immunological, metabolic, hormonal and vascular changes occur, and can cause specific skin diseases. The specific dermatoses of pregnancy have undergone numerous changes in nomenclature and classification, partly due to advances in the knowledge of the pathogenesis of these skin diseases. Currently the following diseases are considered specific dermatoses of pregnancy: pemphigoid gestations, polymorphic eruption of pregnancy, intrahepatic cholestasis of pregnancy and atopic eruption of pregnancy. Timely diagnosis and specific and safe treatment are essential to prevent complications which, although rare, may be associated with significant maternal-fetal comorbidity

    Metabolic turnover and dynamics of modified ribonucleosides by ¹³C labeling

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    Tandem mass spectrometry (MS/MS) is an accurate tool to assess modified ribonucleosides and their dynamics in mammalian cells. However, MS/MS quantification of lowly abundant modifications in non-ribosomal RNAs is unreliable, and the dynamic features of various modifications poorly understood. Here, we developed a 13C labeling approach, called 13C-dynamods, to quantify the turnover of base modifications in newly transcribed RNA. This turnover-based approach helped to resolve mRNA from ncRNA modifications in purified RNA or free ribonucleoside samples, and showed the distinct kinetics of the N6-methyladenosine (m6A) versus 7-methylguanosine (m7G) modification in polyA+-purified RNA. We uncovered that N6,N6-dimethyladenosine (m62A) exhibits distinct turnover in small RNAs and free ribonucleosides when compared to known m62A-modified large rRNAs. Finally, combined measurements of turnover and abundance of these modifications informed on the transcriptional versus posttranscriptional sensitivity of modified ncRNAs and mRNAs, respectively, to stress conditions. Thus, 13C-dynamods enables studies of the origin of modified RNAs at steady-state and subsequent dynamics under non-stationary conditions. These results open new directions to probe the presence and biological regulation of modifications in particular RNAs

    A Paraneoplastic Syndrome to Remember: A Case of Disseminated Intravascular Coagulation in Lung Cancer

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    Disseminated intravascular coagulation (DIC) is an acquired syndrome characterized by the widespread activation of coagulation. It can present as an acute life-threatening emergency or as a chronic process. Mortality is highly dependent on the reversibility of the aetiology and degree of coagulation impairment, so treatment of the underlying cause is vital. The authors present the case of a 57-year-old man whose inaugural presentation of lung cancer was chronic DIC, characterized by three thrombotic events, followed by acute DIC, culminating in death. Metastatic lung cancer was diagnosed only after death

    Leiomioma da Uretra Feminina - Revisão da Literatura a Propósito de Caso Clínico

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    Oleiomioma da uretra é uma patologia rara, estando descritos cerca de uma centena de casos na literatura. São tumores benignos, constituídos por músculo liso e surgem mais frequentemente na idade fértil.Otratamento é cirúrgico com excisão da massa, existindo contudo possibilidade de recidiva local. Apresenta-seumcaso clínico de leiomioma da uretra e realizou-se revisão da literatura

    Non-axisymmetric accretion on the classical TTS RW Aur A

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    (Abridged) High-resolution spectroscopic monitoring of RW Aur A was carried out in 1996, 1998 and 1999 with simultaneous B, V photometry. A multicomponent spectrum is revealed with a veiled photospheric spectrum, broad emissions, narrow emission lines of helium, and accretion, wind and shell features. Periodic modulations in many spectral features were found. The photospheric absorption lines show sinusoidal variations in radial velocity with an amplitude of +-6 km/s and a period of about 2.77 days. The radial velocities of the narrow emission lines of He vary with the same period but in anti-phase to the photospheric lines. The equivalent widths of the narrow emissions vary with a phase-shift with respect to the velocity curve. The strength of the red-shifted accretion components of Na D and other lines is also modulated with the same period. The broad emission lines of metals vary mostly with the double period of about 5.5 days. One unexpected result is that no correlation was found between the veiling and the brightness, although both varied in wide ranges. This is partly due to a contribution of the shell absorption to the photospheric line profiles, which make them vary in width and depth thus simulating lower veiling. Most of the observed features can be interpreted in the framework of non-axisymmetric magnetospheric accretion. We consider two possible models. In the first the asymmetry is induced by orbital motion of an invisible, low mass secondary, which also influences the gasflows around the star, the second considers rotational modulation of a single star with an inclined or asymmetric magnetosphere

    Combined distributed turbo coding and space frequency block coding techniques

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    The distributed space-time (frequency) coding and distributed channel turbo coding used independently represent two cooperative techniques that can provide increased throughput and spectral efficiency at an imposed maximum Bit Error Rate (BER) and delay required from the new generation of cellular networks. This paper proposes two cooperative algorithms that employ jointly the two types of techniques, analyzes their BER and spectral efficiency performances versus the qualities of the channels involved, and presents some conclusions regarding the adaptive employment of these algorithms. © 2010 V. Bota et al.FP7/ICT/2007/21547

    Intramural Vesical Leiomyoma in a Patient with a Pelvic Fibrous Tumour - Case Report

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    Introdução: O leiomioma vesical é um tumor benigno raro que representa,aproximadamente, 0,5% do total de neoplasias da bexiga. É frequentemente um achado imagiológico, sendo a sua localização e dimensões determinantes no desenvolvimento de sintomatologia e no tipo de procedimento a efectuar. Caso Clínico: Reporta-se o caso de um doente com queixas urinárias de disúria, polaquiúria e esforço miccional, inicialmente interpretadas como HBP. A investigação diagnóstica culminou com a enucleação de uma volumosa massa intramural da bexiga, com diagnóstico histológico de leiomioma, num doente com antecedentes de doença de Madelung e excisão prévia de um tumor fibroso paravesical. Discussão: O leiomioma vesical, embora apresentando características imagiológicas típicas, deve ser sempre biopsado para confirmação histológica da sua etiologia. O tumor fibroso pélvico apresenta sempre indicação cirúrgica pois, numa minoria de casos, pode apresentar comportamento agressivo com infiltração dos órgãos adjacentes

    Eye movements as a window to cognitive processes

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    Eye movement research is a highly active and productive research field. Here we focus on how the embodied nature of eye movements can act as a window to the brain and the mind. In particular, we discuss how conscious perception depends on the trajectory of fixated locations and consequently address how fixation locations are selected. Specifically, we argue that the selection of fixation points during visual exploration can be understood to a large degree based on retinotopically structured models. Yet, these models largely ignore spatiotemporal structure in eye-movement sequences. Explaining spatiotemporal structure in eye-movement trajectories requires an understanding of spatiotemporal properties of the visual sampling process. With this in mind, we discuss the availability of external information to internal inference about causes in the world. We demonstrate that visual foraging is a dynamic process that can be systematically modulated either towards exploration or exploitation. For an analysis at high temporal resolution, we suggest a new method: The renewal density allows the investigation of precise temporal relation of eye movements and other actions like a button press. We conclude with an outlook and propose that eye movement research has reached an appropriate stage and can easily be combined with other research methods to utilize this window to the brain and mind to its fullest
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