53,093 research outputs found
Praesphaerammina, a new genus of Cenozoic deep-water agglutinated foraminifera from the Carpathian flysch deposits
No full textThe genus Praesphaerammina Kaminski and Filipcscu is newly described based on a revision of the type species Cystammina subgaleata Vasicek 1947. The genus differs from the Holocene genus Sphaerammina Cushman 1910 emend. Loeblich and Tappan 1964, in possessing a less embracing final chamber and in its interio-areal to areal aperture that lacks any tooth. The definition of the subfamily Sphaeramminae is accordingly emended as well. The genus is common in the Eocene of the Carpathian flysch deposits, but the type species Praesphaerammina subgaleata (Vasicek 1947) is also observed in the Caribbean region and West Africa, where it ranges into the Miocene
The response of modern benthic foraminiferal assemblages to water mass properties along the southern shelf of the Marmara Sea.
No full text"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Letter from C. D. Dawson, Tusayan Copper Mining and Smelting, to Carl Hayden
No full textLetter from C. D. Dawson to Carl Hayden urging him to consider the rights of miners and farmers when drawing up the boundaries for the proposed park
Measurement of the D+/- production asymmetry in 7 TeV pp collisions
No full textThe asymmetry in the production cross-section \sigma of D+/- mesons, A_P = (\sigma(D+) - \sigma(D-))/(\sigma(D+) + \sigma(D-)), is measured in bins of pseudorapidity \eta and transverse momentum p_T within the acceptance of the LHCb detector. The result is obtained with a sample of D+ -> K_S pi+ decays corresponding to an integrated luminosity of 1.0 fb^-1, collected in pp collisions at a centre of mass energy of 7 TeV at the Large Hadron Collider. When integrated over the kinematic range 2.0 K_S pi+ decay is negligible. No significant dependence on \eta or p_T is observed
D* (D)over-bar* molecule interpretation of Z(c)(4025)
No full textWe have used QCD sum rules to study the newly observed charged state Z(c)(4025) as a hidden-charm D*(D) over bar* molecular state with the quantum numbers I-G(J(P)) =1(+)(1(+)). Using a D*(D) over bar* molecular interpolating current, we have calculated the two-point correlation function and the spectral density up to dimension eight at leading order in alpha(s). The extracted mass is m(X) = (4.04 +/- 0.24) GeV. This result is compatible with the observed mass of Z(c)(4025) within the errors, which implies a possible molecule interpretation of this new resonance. We also predict the mass of the corresponding hidden-bottom B*(B) over bar* molecular state: m(Zb) = (9.98 +/- 0.21) GeV.Physics, Particles & FieldsSCI(E)[email protected]; [email protected]; [email protected]; [email protected]
Growth and characterizations of nanostructured tungsten oxides
No full textTungsten oxide (WO3) as nanostructured thin film is an attractive compound to be used for sensors applications. We report on WO3 nanostructured thin films deposited by radio-frequency plasma assisted laser ablation technique. A tungsten oxide ceramic target was irradiated at 193 nm wavelength; the depositions have been carried out in a gas mixture of oxygen and argon on heated substrates (corning glass and silicon) up to 600°C. The gas pressure varied between 1 Pa and 10 Pa. The influence of the substrate temperature, gas pressure and RF power on properties of the obtained nanostructures was investigated by Atomic Force Microscopy, Raman spectroscopy, Secondary Ion Mass Spectrometry and spectro-ellipsometry
Prompt charm production in pp collisions at √<span style="text-decoration:overline">s</span>=7 TeV
No full textCharm production at the LHC in pp collisions at s√=7 TeV is studied with the LHCb detector. The decays D0→K−π+, D+→K−π+π+, D⁎+→D0(K−π+)π+, D+s→ϕ(K−K+)π+, Λ+c→pK−π+, and their charge conjugates are analysed in a data set corresponding to an integrated luminosity of 15 nb−1. Differential cross-sections dσ/dpT are measured for prompt production of the five charmed hadron species in bins of transverse momentum and rapidity in the region 0<pT<8 GeV/c and 2.0<y<4.5. Theoretical predictions are compared to the measured differential cross-sections. The integrated cross-sections of the charm hadrons are computed in the above pT-y range, and their ratios are reported. A combination of the five integrated cross-section measurements gives
σ(cc¯)pT<8 GeV/c,2.0<y<4.5=1419±12(stat)±116(syst)±65(frag) μb,
where the uncertainties are statistical, systematic, and due to the fragmentation functions
Z(c)(3900) as a (D)over-barD* molecule from the pole counting rule
No full textA comprehensive study on the nature of the Zc(3900) resonant structure is carried out in this work. By constructing the pertinent effective Lagrangians and considering the important final-state-interaction effects, we first give a unified description to all the relevant experimental data available, including the J/psi pi and pi invariant mass distributions from the e(+)e(-) -> J/psi pi process, the h(c)pi distribution from e(+)e(-) -> h(c)pi pi, and also the D (D) over bar* spectrum in the e(+)e(-) -> D (D) over bar*pi process. After fitting the unknown parameters to the previous data, we search the pole in the complex energy plane and find only one pole in the nearby energy region in different Riemann sheets. Therefore, we conclude that Z(c)(3900) is of D (D) over bar* molecular nature, according to the pole counting rule method [Nucl. Phys. A543, 632 (1992); Phys. Rev. D 35, 1633 (1987)]. We emphasize that the conclusion based upon the pole counting method is not trivial, since both the D (D) over bar* contact interactions and the explicit Z(c) exchanges are introduced in our analyses andNational Nature Science Foundations of China (NSFC) [10925522, 11021092, 11575052, 11105038]; Natural Science Foundation of Hebei Province [A2015205205]; inoGerman Collaborative Research Center "Symmetries and the Emergence of Structure in QCD" [CRC 110]; DFG; NSFCSCI(E)ARTICLE119
Numerical analysis of a 3-D printed porous trailing edge for broadband noise reduction
No full textLattice Boltzmann simulations were carried out to investigate the noise mitigation mechanisms of a 3-D printed porous trailing-edge insert, elucidating the link between noise reduction and material permeability. The porous insert is based on a unit cell resembling a lattice of diamond atoms. It replaces the last 20 % chord of a NACA 0018 at zero angle-of-attack. A partially blocked insert is considered by adding a solid partition between 84 % and 96 % of the aerofoil chord. The regular porous insert achieves a substantial noise reduction at low frequencies, although a slight noise increase is found at high frequencies. The partially blocked porous insert exhibits a lower noise reduction level, but the noise emission at mid-to-high frequency is slightly affected. The segment of the porous insert near the tip plays a dominant role in promoting noise mitigation, whereas the solid-porous junction contributes, in addition to the rough surface, towards the high-frequency excess noise. The current study demonstrates the existence of an entrance length associated with the porous material geometry, which is linked to the pressure release process that is responsible for promoting noise mitigation. This process is characterised by the aerodynamic interaction between pressure fluctuations across the porous medium, which is found at locations where the porous insert thickness is less than twice the entrance length. Present results also suggest that the noise attenuation level is related to both the chordwise extent of the porous insert and the streamwise turbulent length scale. The porous inserts also cause a slight drag increase compared to their solid counterpart. Wind Energ
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