372 research outputs found
Muon Contribution to Cathodoluminescence Tests?
Tests of composites incorporating highly disordered insulating materials that were bombarded with low-flux keV electron beams exhibited three distinct forms of light emission: short-duration (\u3c\u3c1 s), high intensity luminous electrostatic discharges between the insulator and ground--termed “arcs”; intermediate-duration (10-100 s), intense surface emissions—termed “flares”; and lower intensity, continuous surface cathodoluminescent “glow”. During long-duration experiments at temperatures \u3c150 K, relatively intense flare events occurred at rates of ~2 per min. Rapid increase in photon emission and electron displacement current were observed, with long exponential decay times \u3e1 min. We propose that the source of the flares is the interactions of high energy muons—of cosmic ray origin—with the highly-charged insulating components of the composite materials, which trigger avalanche electrostatic discharge and subsequent recharging along with concomitant light emission. We review evidence from the insulator conductivity at low temperatures, the rates and magnitude of surface charging, the flare frequency, and the magnitude and time-dependence of currents and light emission with regard to this muon hypothesis. Finally, a muon coincidence detection experiment using scintillation detectors is proposed to investigate the potential correlation between incident muons and the observed flares
Los retablos-tabernáculo: variedad dentro de la unidad
ProducciĂłn CientĂficaLos retablos se encuentran entre los logros más destacados y celebrados del arte medieval. Eran el fruto de los esfuerzos conjuntos, habilidades y ambiciones de artistas y mecenas. A menudo, combinando diferentes medios, reflejaban gran parte de la fe, ideales, esperanzas, ansiedades y devociones de las comunidades cristianas. Se erigieron retablos en iglesias de toda clase, desde catedrales y monumentales abadĂas hasta modestas iglesias rurales. Con los años, los retablos medievales se hicieron cada vez más grandes y más complejos. Se convirtieron en sĂmbolos de la identidad y el orgullo de las comunidades y los individuos, para quienes a veces incluso se convirtieron en objeto de emulaciĂłn.Ministerio de EconomĂa, Industria y Competitividad, AEI, FEDER, UE (HAR2017-82949-P
A theoretical framework for trading experiments
A general framework is suggested to describe human decision making in a
certain class of experiments performed in a trading laboratory. We are in
particular interested in discerning between two different moods, or states of
the investors, corresponding to investors using fundamental investment
strategies, technical analysis investment strategies respectively. Our
framework accounts for two opposite situations already encountered in
experimental setups: i) the rational expectations case, and ii) the case of
pure speculation. We consider new experimental conditions which allow both
elements to be present in the decision making process of the traders, thereby
creating a dilemma in terms of investment strategy. Our theoretical framework
allows us to predict the outcome of this type of trading experiments, depending
on such variables as the number of people trading, the liquidity of the market,
the amount of information used in technical analysis strategies, as well as the
dividends attributed to an asset. We find that it is possible to give a
qualitative prediction of trading behavior depending on a ratio that quantifies
the fluctuations in the model
Self-energy and critical temperature of weakly interacting bosons
Using the exact renormalization group we calculate the momentum-dependent
self-energy Sigma (k) at zero frequency of weakly interacting bosons at the
critical temperature T_c of Bose-Einstein condensation in dimensions 3 <= D <
4. We obtain the complete crossover function interpolating between the critical
regime k << k_c, where Sigma (k) propto k^{2 - eta}, and the short-wavelength
regime k >> k_c, where Sigma (k) propto k^{2 (D-3)} in D> 3 and Sigma (k)
\propto ln (k/k_c) in D=3. Our approach yields the crossover scale k_c on the
same footing with a reasonable estimate for the critical exponent eta in D=3.
From our Sigma (k) we find for the interaction-induced shift of T_c in three
dimensions Delta T_c / T_c approx 1.23 a n^{1/3}, where a is the s-wave
scattering length and n is the density.Comment: 4 pages,1 figur
A Powerful New Quantitative Genetics Platform, Combining Caenorhabditis elegans High-Throughput Fitness Assays with a Large Collection of Recombinant Strains.
The genetic variants underlying complex traits are often elusive even in powerful model organisms such as Caenorhabditis elegans with controlled genetic backgrounds and environmental conditions. Two major contributing factors are: (1) the lack of statistical power from measuring the phenotypes of small numbers of individuals, and (2) the use of phenotyping platforms that do not scale to hundreds of individuals and are prone to noisy measurements. Here, we generated a new resource of 359 recombinant inbred strains that augments the existing C. elegans N2xCB4856 recombinant inbred advanced intercross line population. This new strain collection removes variation in the neuropeptide receptor gene npr-1, known to have large physiological and behavioral effects on C. elegans and mitigates the hybrid strain incompatibility caused by zeel-1 and peel-1, allowing for identification of quantitative trait loci that otherwise would have been masked by those effects. Additionally, we optimized highly scalable and accurate high-throughput assays of fecundity and body size using the COPAS BIOSORT large particle nematode sorter. Using these assays, we identified quantitative trait loci involved in fecundity and growth under normal growth conditions and after exposure to the herbicide paraquat, including independent genetic loci that regulate different stages of larval growth. Our results offer a powerful platform for the discovery of the genetic variants that control differences in responses to drugs, other aqueous compounds, bacterial foods, and pathogenic stresses
Radiocaesium (137Cs) in marine mammals from Svalbard, the Barents Sea and the North Greenland Sea
Applicability of the Linear delta Expansion for the lambda phi^4 Field Theory at Finite Temperature in the Symmetric and Broken Phases
The thermodynamics of a scalar field with a quartic interaction is studied
within the linear delta expansion (LDE) method. Using the imaginary-time
formalism the free energy is evaluated up to second order in the LDE. The
method generates nonperturbative results that are then used to obtain
thermodynamic quantities like the pressure. The phase transition pattern of the
model is fully studied, from the broken to the symmetry restored phase. The
results are compared with those obtained with other nonperturbative methods and
also with ordinary perturbation theory. The results coming from the two main
optimization procedures used in conjunction with the LDE method, the Principle
of Minimal Sensitivity (PMS) and the Fastest Apparent Convergence (FAC) are
also compared with each other and studied in which cases they are applicable or
not. The optimization procedures are applied directly to the free energy.Comment: 13 pages, 10 eps figures, revtex, replaced with published versio
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