29,129 research outputs found
Binomial-coefficient multiples of irrationals
Denote by a random infinite path in the graph of Pascal's triangle (left
and right turns are selected independently with fixed probabilities) and by
the binomial coefficient at the 'th level along the path . Then
for a dense set of in the unit interval, is almost surely dense but not uniformly distributed modulo 1.Comment: 10 pages, to appear in Monatshefte f. Mat
Does being different matter?
Changes in the demographic structure of the U.S. population will affect many aspects of the US economy as we move into the next century. Concerns about the impact of an aging population on savings and interest rates, the financing of government spending programs for the elderly, and the possibility of higher taxes for future generations to pay for them have become hot topics, both in the press and among economists. Another concern is whether rising immigration will place an even greater burden on the government. In this article, Finn Kydland and D'Ann Petersen present a framework economists can use to shed ight quantitatively on such issues where individual differences matter. They also discuss why, for a certain class of questions, being different does not matter. In the final section, the authors present findings from current research that deals with the issues mentioned above.Emigration and immigration ; Social security ; Saving and investment
Study of techniques for the reduction of creep in plated wire memories Final report, 28 Jun. 1967 - 28 Aug. 1968
Magnetization reversal in thin films of plated wire memory element
Cell migration on material-driven fibronectin microenvironments
Cell migration is a fundamental process involved in a wide range of biological phenomena. However, how the underlying mechanisms that control migration are orchestrated is not fully understood. In this work, we explore the migratory characteristics of human fibroblasts using different organisations of fibronectin (FN) triggered by two chemically similar surfaces, poly(ethyl acrylate) (PEA) and poly(methyl acrylate) (PMA); cell migration is mediated via an intermediate layer of fibronectin (FN). FN is organised into nanonetworks upon simple adsorption on PEA whereas a globular conformation is observed on PMA. We studied cell speed over the course of 24 h and the morphology of focal adhesions in terms of area and length. Additionally, we analysed the amount of cell-secreted FN as well as FN remodelling. Velocity of human fibroblasts was found to exhibit a biphasic behaviour on PEA, whereas it remained fairly constant on PMA. FA analysis revealed more mature focal adhesions on PEA over time contrary to smaller FAs found on PMA. Finally, human fibroblasts seemed to remodel adsorbed FN more on PMA than on PEA. Overall, these results indicate that the cell–protein–material interface affects cell migratory behaviour. Analysis of FAs together with FN secretion and remodelling were associated with differences in cell velocity providing insights into the factors that can modulate cell motility
Hadronic and electromagnetic probes of hot and dense matter in a Boltzmann+Hydrodynamics model of relativistic nuclear collisions
We present recent results on bulk observables and electromagnetic probes
obtained using a hybrid approach based on the Ultrarelativistic Quantum
Molecular Dynamics transport model with an intermediate hydrodynamic stage for
the description of heavy-ion collisions at AGS, SPS and RHIC energies. After
briefly reviewing the main results for particle multiplicities, elliptic flow,
transverse momentum and rapidity spectra, we focus on photon and dilepton
emission from hot and dense hadronic matter.Comment: To appear in the proceedings of WISH 2010: International Workshop on
Interplay between Soft and Hard interactions in particle production at
ultrarelativistic energies, Catania, Italy, 8-10 September 201
Fast fluorescence dynamics in non-ratiometric calcium indicators
A fluorescence decay of high-affinity non-ratiometric Ca2+ indicator Oregon
Green BAPTA-1 (OGB-1) is analyzed with unprecedented temporal resolution in the
two-photon excitation regime. A triple exponential decay is shown to best fit
the fluorescence dynamics of OGB-1. We provide a new model for accurate
measurements of the free Ca2+ concentration and dissociation constants of
non-ratiometric calcium indicators.Comment: 3 pages, 2 figures, figures revised, added chi-square goodness of fi
Inventory Investment, Internal-Finance Fluctuation, and the Business Cycle
macroeconomics, inventory investment, internal-finance fluctuation, business cycle
Ultrafast Resonant Polarization Interferometry: Towards the First Direct Detection of Vacuum Polarization
Vacuum polarization, an effect predicted nearly 70 years ago, is still yet to
be directly detected despite significant experimental effort. Previous attempts
have made use of large liquid-helium cooled electromagnets which inadvertently
generate spurious signals that mask the desired signal. We present a novel
approach for the ultra-sensitive detection of optical birefringence that can be
usefully applied to a laboratory detection of vacuum polarization. The new
technique has a predicted birefringence measurement sensitivity of in a 1 second measurement. When combined with the extreme
polarizing fields achievable in this design we predict that a vacuum
polarization signal will be seen in a measurement of just a few days in
duration.Comment: 9 pages, 2 figures. submitted to PR
How Sensitive are Di-Leptons from Rho Mesons to the High Baryon Density Region?
We show that the measurement of di-leptons might provide only a restricted
view into the most dense stages of heavy ion reactions. Thus, possible studies
of meson and baryon properties at high baryon densities, as e.g. done at
GSI-HADES and envisioned for FAIR-CBM, might observe weaker effects than
currently expected in certain approaches. We argue that the strong absorption
of resonances in the high baryon density region of the heavy ion collision
masks information from the early hot and dense phase due to a strong increase
of the total decay width because of collisional broadening. To obtain
additional information, we also compare the currently used approaches to
extract di-leptons from transport simulations - i.e. shining, only vector
mesons from final baryon resonance decays and instant emission of di-leptons
and find a strong sensitivity on the method employed in particular at FAIR and
SPS energies. It is shown explicitly that a restriction to rho meson (and
therefore di-lepton) production only in final state baryon resonance decays
provide a strong bias towards rather low baryon densities. The results
presented are obtained from UrQMD v2.3 calculations using the standard set-up.Comment: 8 pages, 6 figures, expanded versio
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