752 research outputs found
Harmonic measures for distributions with finite support on the mapping class group are singular
Kaimanovich and Masur showed that a random walk on the mapping class group
for an initial distribution with finite first moment and whose support
generates a non-elementary subgroup, converges almost surely to a point in the
space PMF of projective measured foliations on the surface. This defines a
harmonic measure on PMF. Here, we show that when the initial distribution has
finite support, the corresponding harmonic measure is singular with respect to
the natural Lebesgue measure on PMF.Comment: 43 pages, 16 figures. Minor improvements overall, specifically
Section 12. Added reference
-factorization approach to the Higgs boson production in channel at the LHC
We calculated a differential cross section of the Higgs boson production in
the decay channel within the framework of
-factorization. Results are obtained using an off-shell matrix element for
the process together with
Ciafaloni-Catani-Fiorani-Marchesini (CCFM) evolution equations for an
unintegrated gluon distribution function. We have presented a comparison of our
results with the latest experimental measurements at = 8 TeV and
= 13 TeV from the ATLAS and CMS collaborations at the LHC. In
addition to this, we have compared our results with the results from the
collinear factorization formalism calculated up to next-to-next-to-leading
order plus next-to-next-to-leading logarithm (NNLO + NNLL) accuracy obtained
using the HRes code for the Higgs boson production in the gluon-gluon fusion
process. Our estimates are consistently close to NNLO + NNLL results obtained
using a collinear factorization formalism and are also in agreement with
experimental measurements.Comment: 10 pages, 5 figures updated using TMDli
Histoplasma capsulatum Infection in an Allogeneic Hematopoietic Stem Cell Transplant Patient Receiving Voriconazole Prophylaxis
Histoplasma capsulatum infection is a rare complication in the allogeneic stem cell transplant patients. Minimal guidance exists on how to appropriately manage histoplasmosis in these patients. We report a patient who developed Histoplasma pneumonia while receiving voriconazole prophylaxis at a therapeutic trough level. The patient experienced significant clinical improvement after initiation of itraconazole pharmacotherapy. We recommend a lower threshold for evaluation for histoplasmosis in allogeneic hematopoietic stem cell transplant recipients who live in endemic regions, regardless of their antifungal prophylactic regimen
Symmetry breaking by quantum coherence in single electron attachment
Quantum coherence-induced effects in atomic and molecular systems are the basis of several proposals for laser-based control of chemical reactions. So far, these rely on coherent photon beams inducing coherent reaction pathways that may interfere with one another, in order to achieve the desired outcome. This concept has been successfully exploited for removing the inversion symmetry in the dissociation of homonuclear diatomic molecules, but it remains to be seen if such quantum coherent effects can also be generated by interaction of incoherent electrons with such molecules. Here we show that resonant electron attachment to H2 and the subsequent dissociation into H (n=2) + H− is asymmetric about the inter-nuclear axis, while the asymmetry in D2 is far less pronounced. We explain this observation as due to attachment of a single electron resulting in a coherent superposition of two resonances of opposite parity. In addition to exemplifying a new quantum coherent process, our observation of coherent quantum dynamics involves the active participation of all three electrons and two nuclei, which could provide new tools for studying electron correlations as a means to control chemical processes and demonstrates the role of coherent effects in electron induced chemistry
Transverse Single Spin Asymmetries and Charmonium Production
We estimate transverse spin single spin asymmetry(TSSA) in the process
using color evaporation model of charmonium
production. We take into account transverse momentum dependent(TMD) evolution
of Sivers function and parton distribution function and show that the there is
a reduction in the asymmetry as compared to our earlier estimates wherein the
- evolution was implemented only through DGLAP evolution of unpolarized
gluon densities.Comment: Proceedings of Light Cone 2012, New Delhi, Indi
IMPROVING STARTABILITY AND REDUCING EMISSIONS IN FLEXFUEL SPARK IGNITION DIRECT INJECTION VARIABLE CAM TIMING ENGINE
Experimental work and analysis was done to investigate engine startup robustness and emissions of a flex-fuel spark ignition (SI) direct injection (DI) engine. The vaporization and other characteristics of ethanol fuel blends present a challenge at engine startup. Strategies to reduce the enrichment requirements for the first engine startup cycle and emissions for the second and third fired cycle at 25°C ± 1°C engine and intake air temperature were investigated.
Research work was conducted on a single cylinder SIDI engine with gasoline and E85 fuels, to study the effect on first fired cycle of engine startup. Piston configurations that included a compression ratio change (11 vs 15.5) and piston geometry change (flattop vs bowl) were tested, along with changes in intake cam timing (95,110,125) and fuel pressure (0.4 MPa vs 3 MPa). The goal was to replicate the engine speed, manifold pressure, fuel pressure and testing temperature from an engine startup trace for investigating the first fired cycle for the engine.
Results showed bowl piston was able to enable lower equivalence ratio engine starts with gasoline fuel, while also showing lower IMEP at the same equivalence ratio compared to flat top piston. With E85, bowl piston showed reduced IMEP as compression ratio increased at the same equivalence ratio. A preference for constant intake valve timing across fuels seemed to indicate that flattop piston might be a good flex-fuel piston. Significant improvements were seen with higher CR bowl piston with high fuel pressure starts, but showed no improvement with low fuel pressures.
Simulation work was conducted to analyze initial three cycles of engine startup in GT-POWER for the same set of hardware used in the experimentations. A steady state validated model was modified for startup conditions. The results of which allowed an understanding of the relative residual levels and IMEP at the test points in the cam phasing space. This allowed selecting additional test points that enable use of higher residual levels, eliminating those with smaller trapped mass incapable of producing required IMEP for proper engine turnover.
The second phase of experimental testing results for 2nd and 3rd startup cycle revealed both E10 and E85 prefer the same SOI of 240°bTDC at second and third startup cycle for the flat top piston and high injection pressures. E85 fuel optimal cam timing for startup showed that it tolerates more residuals compared to E10 fuel. Higher internal residuals drives down the Ø requirement for both fuels up to their combustion stability limit, this is thought to be direct benefit to vaporization due to increased cycle start temperature. Benefits are shown for an advance IMOP and retarded EMOP strategy at engine startup.
Overall the amount of residuals preferred by an engine for E10 fuel at startup is thought to be constant across engine speed, thus could enable easier selection of optimized cam positions across the startup speeds
- …