693 research outputs found
On the capacity and normalisation of ISI channels
[Abstract]: We investigate the capacity of various ISI channels with additive white Gaussian noise. Previous papers showed
a minimum Eb/N0 of â4.6 dB, 3 dB below the capacity of
a flat channel, is obtained using the water-pouring capacity
formulas for the 1 + D channel. However, these papers did
not take into account that the channel power gain can be
greater than unity when water-pouring is used. We present a
generic power normalization method of the channel frequency
response, namely peak bandwidth normalisation, to facilitate the fair capacity comparison of various ISI channels. Three types of ISI channel, i.e., adder channels, RC channels and magnetic recording channels, are examined. By using our channel power gain normalization, the capacity curves of these ISI channels are shown
Relaxation Dynamics of Electronically Excited C60â in o-Dichlorobenzene and Tetrahydrofuran Solution
The ultrafast response of singly negatively charged C60 fullerene in solution has been investigated by femtosecond pump-probe absorption spectroscopy and transient anisotropy in the visible and near-infrared region. Pump excitation within the near-infrared band demonstrates that this spectral feature can be described as avibrational progression associated with asingle electronic transition. Relaxation of the first electronically excited state occurs primarily by internal conversion with atime constant of 3ps, slightly depending on the solvents, tetrahydrofuran or o-dichlorobenzene, and also on the excitation wavelength. An excitation of the second electronically excited state around 530nm leads to an ultrafast internal conversion to the first excited state with apulse-limited time constant of less than 100fs. As aminor channel, stimulated emission in the spectral regime of 1150-1300nm was observed from the first electronically excited state both after near-infrared and visible excitation. After internal conversion to the electronic ground state, C60â dissipates its excess internal energy into the solvent on alonger timescale of 40-70ps. The transient anisotropy associated with directly populating the first excited state reveals an ultrafast component decaying within 100fs, which is attributed to ultrafast vibrational motions, conceivably arising from excited state pseudorotatio
Proyecto piloto 9x18, una alternativa a la expansiĂłn de Santiago
Ponencia que describe el proyecto pĂloto 9x18 que consiste en la construcciĂłn de una nueva vivienda para los allegados en los lotes donde habitan, sin necesidad de adquirir un terreno nuevo
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A nationwide study on cancer recurrences, second primary tumours, distant metastases and survival after treatment for primary head and neck cancer in the Netherlands
Introduction: There is no consensus on the optimal duration of post-treatment follow-up after head and neck cancer (HNC). To generate site-specific input for follow-up guidelines, this study describes the incidence and timing of manifestations of disease during five years of follow-up. Methods: All patients diagnosed with HNC in the Netherlands in 2015 were selected from the Netherlands Cancer Registry. The follow-up events local recurrence (LR), regional recurrence (RR), second primary tumour (SPT), distant metastasis (DM) and death were studied per follow-up-year. The cumulative incidence of these events was calculated using competing risk analyses, with LR, RR and SPT of the head and neck (SPHNC) as events and SPT outside the head-neck (SPOHN), DM and death as competing events. Analyses were performed for oral cavity-, oropharynx-, larynx- and hypopharynx squamous cell carcinoma (SCC), and all HNC patients. Results: The 1-, 1.5-, and 2-year cumulative incidence of an event (LR, RR, SPHNC) were 10% (95%CI 8â13), 12% (95%CI 10â15), and 13% (95%CI 10â16) for oral cavity SCC; 6% (95%CI 4â9), 10% (95%CI 7â14), and 11% (95%CI 8â15) for oropharynx SCC; 7% (95%CI 5â10), 11% (95%CI 9â15), and 13% (95%CI 10â16) for larynx SCC and 11% (95%CI 6â19), 19% (95%CI 12â27), and 19% (95%CI 12â27) for hypopharynx SCC. Conclusions: One year of follow-up for oral cavity SCC, and 1.5 years for oropharynx-, larynx-, and hypopharynx SCC suffices for the goal of detecting disease manifestations after treatment. More research into other aspects of follow-up care should be performed to determine the optimal follow-up regimen.</p
Ervaringen met witte klaver op zandgrond
Op ROC Aver Heino is in 1993 een proef gestart, waarin de invloed van bemesting en klaverrassen beoordeeld is op de totale produktie en met name de ontwikkeling van de eerste snede in het voorjaar
Recombinant human tissue factor pathway inhibitor exerts anticoagulant, anti-inflammatory and antibacterial effects in murine pneumococcal pneumonia
Generalized thermodynamics and Fokker-Planck equations. Applications to stellar dynamics, two-dimensional turbulence and Jupiter's great red spot
We introduce a new set of generalized Fokker-Planck equations that conserve
energy and mass and increase a generalized entropy until a maximum entropy
state is reached. The concept of generalized entropies is rigorously justified
for continuous Hamiltonian systems undergoing violent relaxation. Tsallis
entropies are just a special case of this generalized thermodynamics.
Application of these results to stellar dynamics, vortex dynamics and Jupiter's
great red spot are proposed. Our prime result is a novel relaxation equation
that should offer an easily implementable parametrization of geophysical
turbulence. This relaxation equation depends on a single key parameter related
to the skewness of the fine-grained vorticity distribution. Usual
parametrizations (including a single turbulent viscosity) correspond to the
infinite temperature limit of our model. They forget a fundamental systematic
drift that acts against diffusion as in Brownian theory. Our generalized
Fokker-Planck equations may have applications in other fields of physics such
as chemotaxis for bacterial populations. We propose the idea of a
classification of generalized entropies in classes of equivalence and provide
an aesthetic connexion between topics (vortices, stars, bacteries,...) which
were previously disconnected.Comment: Submitted to Phys. Rev.
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