210 research outputs found
Experimental evidence for Wigner's tunneling time
Tunneling of a particle through a potential barrier remains one of the most
remarkable quantum phenomena. Owing to advances in laser technology, electric
fields comparable to those electrons experience in atoms are readily generated
and open opportunities to dynamically investigate the process of electron
tunneling through the potential barrier formed by the superposition of both
laser and atomic fields. Attosecond-time and angstrom-space resolution of the
strong laser-field technique allow to address fundamental questions related to
tunneling, which are still open and debated: Which time is spent under the
barrier and what momentum is picked up by the particle in the meantime? In this
combined experimental and theoretical study we demonstrate that for
strong-field ionization the leading quantum mechanical Wigner treatment for the
time resolved description of tunneling is valid. We achieve a high sensitivity
on the tunneling barrier and unambiguously isolate its effects by performing a
differential study of two systems with almost identical tunneling geometry.
Moreover, working with a low frequency laser, we essentially limit the
non-adiabaticity of the process as a major source of uncertainty. The agreement
between experiment and theory implies two substantial corrections with respect
to the widely employed quasiclassical treatment: In addition to a non-vanishing
longitudinal momentum along the laser field-direction we provide clear evidence
for a non-zero tunneling time delay. This addresses also the fundamental
question how the transition occurs from the tunnel barrier to free space
classical evolution of the ejected electron.Comment: 31 pages, 15 figures including appendi
Development of a tritium permeation barrier on F82H-mod. Sheets and on MANET tubes by hot dip aluminising and subsequent heat treatment
Entwicklung von Tritiumpermeationshemmenden Schichten auf F82H-mod. Blechen und MANET Rohren nach dem Hot-Dip Aluminierverfahren mit anschließender Wärmebehandlung
In der vorliegenden Arbeit werden die Ergebnisse von tauchaluminierten Blechproben aus F82H-mod. und Rohrproben aus MANET diskutiert. Die anschließende Wärmebehandlung an den getauchten Proben (1040°C, 0.5 h / 750°C, 1 h bzw. 1075°C, 0.5 h / 750°C, 2 h) entspricht der Vergütungsvorschrift für F82H-mod. bzw. der für MANET.
Das Hot-Dip Aluminierverfahren mit anschließender Wärmebehandlung eignet sich als Beschichtungsmethode sowohl für Blechproben als auch für die Innen- und Außenbeschichtung von Rohren. Die Zusammensetzung und Dicke der hergestellten Schichten ist unabhängig vom eingesetzten Stahl. Des weiteren wird gezeigt, daß die hergestellten Aluminidschichten in Pb-17Li beständig sind, der PRF genügend hoch ist und die einzelnen Prozeßschritte mit der ITM Geometrie und der Fabrikationssequenz vereinbar sind
A characterization of quadratic-multiplicative mappings
In the spirit of some earlier studies of Jean Dhombres, Roman Ger and
Ludwig Reich we discuss the alienation problem for quadratic and multiplicative
mappings
A composite functional equation from algebraic aspect
In this paper we discuss the composite functional equation
f(x+2f(y))=f(x)+y+f(y)
on an Abelian group. This equation originates from Problem 10854 of the American Mathematical Monthly. We give an algebraic description of the solutions on uniquely 3-divisible Abelian groups, and then we construct all solutions f of this equation on finite Abelian groups without elements of order 3 and on divisible Abelian groups without elements of order 3 including the additive group of real numbers
Application of Volcano Plots in Analyses of mRNA Differential Expressions with Microarrays
Volcano plot displays unstandardized signal (e.g. log-fold-change) against
noise-adjusted/standardized signal (e.g. t-statistic or -log10(p-value) from
the t test). We review the basic and an interactive use of the volcano plot,
and its crucial role in understanding the regularized t-statistic. The joint
filtering gene selection criterion based on regularized statistics has a curved
discriminant line in the volcano plot, as compared to the two perpendicular
lines for the "double filtering" criterion. This review attempts to provide an
unifying framework for discussions on alternative measures of differential
expression, improved methods for estimating variance, and visual display of a
microarray analysis result. We also discuss the possibility to apply volcano
plots to other fields beyond microarray.Comment: 8 figure
Rediscovery of the anti-pancreatic antibodies and evaluation of their prognostic value in a prospective clinical cohort of Crohn's patients: the importance of specific target antigens (GP2 and CUZD1).
BACKGROUNDS:
Glycoprotein 2[GP2] and CUB zona pellucida-like domain 1[CUZD1] belong to protein families involved in gut innate immunity processes and have recently been identified as specific targets of anti-pancreatic autoantibodies [PAbs] in Crohn's disease[CD]. We aimed to determine the prognostic potential of novel target-specific PAbs regarding long-term disease course of an adult CD patient cohort.
METHODS:
Sera of 458 consecutive well-characterised IBD patients from a single referral IBD centre were tested by enzyme-linked immunosorbent assay [ELISA] with isoform 4 of recombinant GP2 [anti-MZGP2 and anti-GP2 IgA/IgG] and indirect immunofluorescence test [IIFT] system with GP2 and CUZD1 expressing transfected HEK 293 cells [anti-rPAg2 and rPAg1 IgA/IgG]. Clinical data were available on complicated disease or surgical interventions as well as disease activity and medical treatment during the prospective follow-up [median, 108 months].
RESULTS:
Totals of 12.4% and 20.8% of CD patients were positive for IgA/IgG type of anti-GP2 and anti-CUZD1, respectively, with a significant difference compared with UC [p < 0.01]. Antibody status was stable over time. Agreement among three different anti-GP2 assays was good. Positivity for PAbs, mainly IgA subtypes, predicted a faster progression towards complicated disease course. In Kaplan-Meier analysis, time to surgery or development of perianal disease was associated with anti-GP2 IgA [pLogRank < 0.01] or anti-CUZD1 IgA [pLogRank < 0.001] positivity, respectively. Anti-CUZD1 IgA remained an independent predictor in the multivariate Cox-regression model (hazard ratio [HR]: 3.43, 95% confidence interval [CI]: 1.68-7.02, p < 0.001).
CONCLUSIONS:
The present study has shown that specific PAbs [especially IgA subtype] predict complicated disease course including the development of perianal disease in CD
Search for the Magnetic Monopole at a Magnetoelectric Surface
We show, by solving Maxwell’s equations, that an electric charge on the surface of a slab of a linear magnetoelectric material generates an image magnetic monopole below the surface provided that the magnetoelectric has a diagonal component in its magnetoelectric response. The image monopole, in turn, generates an ideal monopolar magnetic field outside of the slab. Using realistic values of the electric and magnetic field susceptibilities, we calculate the magnitude of the effect for the prototypical magnetoelectric material Cr2O3. We use low-energy muon spin rotation to measure the strength of the magnetic field generated by charged muons as a function of their distance from the surface of a Cr2O3 film and show that the results are consistent with the existence of the monopole. We discuss other possible routes to detecting the monopolar field, and show that, while the predicted monopolar field generated by Cr2O3 is above the detection limit for standard magnetic force microscopy, the detection of the field using this technique is prevented by surface charging effects
Atmospheric neutrino oscillation analysis with sub-leading effects in Super-Kamiokande I, II, and III
We present a search for non-zero theta_{13} and deviations of sin^2
theta_{23} from 0.5 in the oscillations of atmospheric neutrino data from
Super-Kamiokande -I, -II, and -III. No distortions of the neutrino flux
consistent with non-zero theta_{13} are found and both neutrino mass hierarchy
hypotheses are in agreement with the data. The data are best fit at Delta m^2 =
2.1 x 10^-3 eV^2, sin^2 theta_{13} = 0.0, and sin^2 theta_{23} =0.5. In the
normal (inverted) hierarchy theta_{13} and Delta m^2 are constrained at the
one-dimensional 90% C.L. to sin^2 theta_{13} < 0.04 (0.09) and 1.9 (1.7) x
10^-3 < Delta m^2 < 2.6 (2.7) x 10^-3 eV^2. The atmospheric mixing angle is
within 0.407 <= sin^2 theta_{23} <= 0.583 at 90% C.L.Comment: 17 Pages, 14 figures. To be submitted to Phys. Rev. D Minor update to
text after referee comments. Figures modified for better grayscale printing
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