Litherland has shown that if a knot is (+)-amphicheiral then its m-twist-spin is reversible. We show that, for classical knots, in many cases the converse holds. The irreversibility (sometimes called noninvertibility) of certain twist-spun knots has been established by Ruberman [10], using the Farber-Levine linking pairing and the Casson-Gordon invariants. More recently, alternative proofs of t...

We present a systematic study of twist-3 light-cone distribution amplitudes of K and φ mesons in QCD. The structure of SU(3)-breaking corrections is studied in detail. Nonperturbative input parameters are estimated from QCD sum rules. As a by-product, we update the parameters describing the twist-3 distribution amplitudes of the ρ meson. We also review and update predictions for the twist-2 dis...

QCD analysis of the CCFR data for xF 3 and Higher–Twist Contribution. Abstract The QCD analysis of the xF 3 structure function measured in deep-inelastic scattering of neutrinos and antineutrinos on an iron target at the Fermilab Tevatron is done in 1–, 2– and 3–loop order of QCD. The x dependence of the higher–twist contribution is evaluated. The experimental value of higher–twist corrections ...

The status of the twist–2 and the twist–3 integral relations between polarized structure functions in deep inelastic scattering is discussed. The relations can be tested in the upcoming experiments in the range Q ∼ > M 2 p . Contribution to the Proceedings of the Workshop on Polarized Protons at High Energies – Accelerator Challenges and Physics Opportunities, DESY, May 1999, eds. D. Barber, A....

Twist, a master regulator of embryonic morphogenesis, induces functions that are also required for tumor invasion and metastasis. Because thrombin contributes to the malignant phenotype by up-regulating tumor metastasis, we examined its effect on Twist in five different tumor cell lines and two different endothelial cell lines. Thrombin up-regulated Twist mRNA and protein in all seven cell line...

We investigate wide-angle photoproduction of the ${\ensuremath{\eta}}^{\ensuremath{'}}$-meson within handbag approach to twist-3 accuracy. It turns out that, due gluon content ${\ensuremath{\eta}}^{\ensuremath{'}}$, this process is dominated by twist 2 in contrast with pion and $\ensuremath{\eta}$ photoproduction. Using presently available information on twist-2 distribution amplitudes $\ensure...

We compute the nucleon matrix elements of QCD operators of twist 3 and 4 in the instanton vacuum. We consider the operators determining 1/Q 2 –power corrections to the Bjorken, Ellis–Jaffe and Gross–Llewellyn-Smith sum rules. The nucleon is described as a soliton of the effective chiral theory derived from instantons in the 1/N c –expansion. QCD operators involving the gluon field are systemati...

In wide kinematic regions the deeply inelastic structure functions can be described by their leading twist contributions within Quantum Chromodynamics (QCD). Higher twist corrections [1] emerge both in the region of large [2,3] and small values [4,5] of the Bjorken variable x. The leading twist sector, both for unpolarized and polarized deeply inelastic scattering, is well explored within pertu...

background: left ventricular (lv) twist is due to oppositely directed apical and basal rotation and has been proposed as a sensitive marker of lv function. we sought to assess the impact of chronic pure mitral regurgitation (mr) on the torsional mechanics of the left human ventricle using tissue doppler imaging. methods: nineteen severe mr patients with a normal lv ejection fraction and 16 non-...