1,322 research outputs found

    Impulse ultra-wideband signal relaying in ad hoc radio networks

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    A method of impulse ultra-wideband signals relaying in ad hoc radio networks is described. As the relaying signals a group of chipsets is used to represent various minimal information units. A system of markers is introduced to unambiguous determine the relaying routes. The chipset representation of transmitted signals reduces the delays coursed by multistep relaying and increases the data transfer rate

    ETS1 is a genome-wide effector of RAS/ERK signaling in epithelial cells

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    The RAS/ERK pathway is commonly activated in carcinomas and promotes oncogenesis by altering transcriptional programs. However, the array of cis-regulatory elements and trans-acting factors that mediate these transcriptional changes is still unclear. Our genome-wide analysis determined that a sequence consisting of neighboring ETS and AP-1 transcription factor binding sites is enriched near cell migration genes activated by RAS/ERK signaling in epithelial cells. In vivo screening of candidate ETS proteins revealed that ETS1 is specifically required for migration of RAS/ERK activated cells. Furthermore, both migration and transcriptional activation through ETS/AP-1 required ERK phosphorylation of ETS1. Genome-wide mapping of multiple ETS proteins demonstrated that ETS1 binds specifically to enhancer ETS/AP-1 sequences. ETS1 occupancy, and its role in cell migration, was conserved in epithelial cells derived from multiple tissues, consistent with a chromatin organization common to epithelial cell lines. Genome-wide expression analysis showed that ETS1 was required for activation of RAS-regulated cell migration genes, but also identified a surprising role for ETS1 in the repression of genes such as DUSP4, DUSP6 and SPRY4 that provide negative feedback to the RAS/ERK pathway. Consistently, ETS1 was required for robust RAS/ERK pathway activation. Therefore, ETS1 has dual roles in mediating epithelial-specific RAS/ERK transcriptional functions

    Langevin dynamics of J/ψJ/\psi in a parton plasma

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    We consider the Brownian motion of a ccˉc \bar c pair produced in the very early satge of a quark-gluon plasma. The one-dimensional Langevin equation is solved formally to get purely mechanical properties at small and large times. Stochastically-averaged variances are examined to extract the time scales associated with swelling and ionization of the bound state. Simple numerical estimates of the time scales are compared with other mechanisms of J/ψJ/\psi suppression.Comment: 18 pages with a figur

    Evidence for a relationship between bilateral coordination during complex gait tasks and freezing of gait in Parkinson\u27s disease

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    BACKGROUND: Freezing of gait is a debilitating and common gait disturbance observed in individuals with Parkinson’s disease (PD). Although the underlying mechanisms of freezing remain unclear, bilateral coordination of steps, measured as a phase coordination index, has been suggested to be related to freezing. Phase coordination index has not, however, been measured during tasks associated with freezing such as turning and backward walking. Understanding how bilateral coordination changes during tasks associated with freezing may improve our understanding of the causes of freezing. METHODS: Twelve individuals with PD who freeze (freezers), 19 individuals with PD who do not freeze (non-freezers), and 10 healthy, age-matched older adults participated. General motor disease severity and freezing severity were assessed. Phase coordination index was calculated for all subjects during forward walking, backward walking, continuous turning in small radius circles, and turning in large radius circles. RESULTS: Freezers and non-freezers had similar disease duration and general motor severity. Stepping coordination (measured as phase coordination index) was significantly worse in freezers compared to non-freezers and controls. Turning and backward walking, tasks related to freezing, resulted in worse coordination with respect to forward walking. Coordination was associated with severity of freezing scores such that worse coordination was correlated with more severe freezing. CONCLUSIONS: These results provide evidence that stepping coordination is related to freezing in people with PD. Identifying variables associated with freezing may provide insights into factors underlying this symptom, and may inform rehabilitative interventions to reduce its occurrence in PD

    Dynamic control of posture across locomotor tasks

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    Successful locomotion depends on postural control to establish and maintain appropriate postural orientation of body segments relative to one another and to the environment, and to ensure dynamic stability of the moving body. This paper provides a framework for considering dynamic postural control, highlighting the importance of coordination, consistency, and challenges to postural control posed by various locomotor tasks such as turning and backward walking. The impacts of aging and various movement disorders on postural control are discussed broadly in an effort to provide a general overview of the field and recommendations for assessment of dynamic postural control across different populations in both clinical and research settings. Suggestions for future research on dynamic postural control during locomotion are also provided and include discussion of opportunities afforded by new and developing technologies, the need for long-term monitoring of locomotor performance in everyday activities, gaps in our knowledge of how targeted intervention approaches modify dynamic postural control, and the relative paucity of literature regarding dynamic postural control in movement disorder populations other than Parkinson disease

    Diva Diversity: National Vocal Schools and Qualities

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    Hearing the term “opera singer” for many triggers an image of a German dramatic soprano bearing viking horns and powerfully bursting into a high C. Yet, what is it that perpetuates this stereotype that German singers possess weighty instruments with dark timbres? Why are classically trained North American vocal students told by their teachers to sing lightly and delicately when performing French mélodie, and not any other genre? Research in vocal pedagogy has demonstrated that singers from particular regions have been typified by their vocal qualities in terms of size and color. These qualities by nation mainly stem from contrasting educational models. Language also plays a role in determining one’s resonance, as native speakers of more guttural languages tend to place their sounds in the throat cavity when they sing, whereas native speakers of languages which border on nasality are prone to focusing their sound in the mask of the face. With this project, I will examine the pedagogical techniques employed in the French, German, Italian, and, to a lesser extent, Slavic and Nordic schools of singing. I will further delve into the musical literature produced by each region, and the performance methodologies presumed to be applied to each. Lastly, I will address modern controversial theories of voice science and morphology in assessing regional vocal quality, ultimately concluding that the stereotypes underlying people’s voices are a result of the theoretical constructs of Western art music, and the ideals set in place by the German Fach system

    Experimental realization of a topological Anderson insulator

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    We experimentally demonstrate that disorder can induce a topologically non-trivial phase. We implement this “Topological Anderson Insulator” in arrays of evanescently coupled waveguides and demonstrate its unique features
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