115,593 research outputs found

    Digital computing cardiotachometer

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    A tachometer is described which instantaneously measures heart rate. During the two intervals between three succeeding heart beats, the electronic system: (1) measures the interval by counting cycles from a fixed frequency source occurring between the two beats; and (2) computes heat rate during the interval between the next two beats by counting the number of times that the interval count must be counted to zero in order to equal a total count of sixty times (to convert to beats per minute) the frequency of the fixed frequency source

    Cardiotachometer displays heart rate on a beat-to-beat basis

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    Electronics for this system may be chosen so that complete calculation and display may be accomplished in a few milliseconds, far less than even the fastest heartbeat interval. Accuracy may be increased, if desired, by using higher-frequency timing oscillator, although this will require large capacity registers at increased cost

    Are the Earth and the Moon compositionally alike? Inferences on lunar composition and implications for lunar origin and evolution from geophysical modeling

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    The main objective of the present study is to discuss in detail the results obtained from an inversion of the Apollo lunar seismic data set, lunar mass, and moment of inertia. We inverted directly for lunar chemical composition and temperature using the model system CaO-FeO-MgO-Al2O3-SiO2. Using Gibbs free energy minimization, stable mineral phases at the temperatures and pressures of interest, their modes and physical properties are calculated. We determine the compositional range of the oxide elements, thermal state, Mg#, mineralogy and physical structure of the lunar interior, as well as constraining core size and density. The results indicate a lunar mantle mineralogy that is dominated by olivine and orthopyroxene ( 80 vol%), with the remainder being composed of clinopyroxene and an aluminous phase (plagioclase, spinel, and garnet present in the depth ranges 0–150 km, 150–200 km, and >200 km, respectively). This model is broadly consistent with constraints on mantle mineralogy derived from the experimental and observational study of the phase lationships and trace element compositions of lunar mare basalts and picritic glasses. In particular, by melting a typical model mantle composition using the pMELTS algorithm, we found that a range of batch melts generated from these models have features in common with low Ti mare basalts and picritic glasses. Our results also indicate a bulk lunar composition and Mg# different to that of the Earth’s upper mantle, represented by the pyrolite composition. This difference is reflected in a lower bulk lunar Mg# ( 0.83). Results also indicate a small iron-like core with a radius around 340 km.The Carlsberg Foundation, NER

    ELF: The electronic learning facilitator

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    As the world‐wide computer network becomes ubiquitous, new tools have been developed, such as the World Wide Web (WWW), for the delivery of multimedia hypertext‐based documents. Similarly, there has been an explosion in the amount of email, bulletin boards, and Usenet News available. This has led to a major problem of information overload: we are slowly but surely being overwhelmed by the amount of information available to us

    Dispersion of biased swimming microorganisms in a fluid flowing through a tube

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    Classical Taylor-Aris dispersion theory is extended to describe the transport of suspensions of self-propelled dipolar cells in a tubular flow. General expressions for the mean drift and effective diffusivity are determined exactly in terms of axial moments, and compared with an approximation a la Taylor. As in the Taylor-Aris case, the skewness of a finite distribution of biased swimming cells vanishes at long times. The general expressions can be applied to particular models of swimming microorganisms, and thus be used to predict swimming drift and diffusion in tubular bioreactors, and to elucidate competing unbounded swimming drift and diffusion descriptions. Here, specific examples are presented for gyrotactic swimming algae.Comment: 20 pages, 4 figures. Published version available at http://rspa.royalsocietypublishing.org/content/early/2010/02/09/rspa.2009.0606.short?rss=

    The Virtual Runner Learning Game

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    A learning game has been developed which allows learners to study and learn about the significance of three important variables in human physiology (lactate, glycogen, and hydration) and their influence on sports performance during running. The player can control the speed of the runner, and as a consequence the resulting physiological processes are simulated in real-time. The performance degradation of the runner due to these processes requires that different strategies for pacing the running speed are applied by the player, depending on the total length of the run. The game has been positively evaluated in a real learning context of academic physiology teaching

    Coulomb force effects in low-energy α\alpha-deuteron scattering

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    The α\alpha-proton Coulomb interaction is included in the description of α\alpha-deuteron scattering using the screening and renormalization approach in the framework of momentum-space three-particle equations. The technical reliability of the method is demonstrated. Large Coulomb-force effects are found.Comment: To be published in Phys. Rev.
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