933 research outputs found
Solving the Coulomb scattering problem using the complex scaling method
Based on the work of Nuttall and Cohen [Phys. Rev. {\bf 188} (1969) 1542] and
Resigno et al{} [Phys. Rev. A {\bf 55} (1997) 4253] we present a rigorous
formalism for solving the scattering problem for long-range interactions
without using exact asymptotic boundary conditions. The long-range interaction
may contain both Coulomb and short-range potentials. The exterior complex
scaling method, applied to a specially constructed inhomogeneous Schr\"odinger
equation, transforms the scattering problem into a boundary problem with zero
boundary conditions. The local and integral representations for the scattering
amplitudes have been derived. The formalism is illustrated with numerical
examples.Comment: 3 pages, 3 figure
Predicting participation in group parenting education in an Australian sample: The role of attitudes, norms, and control factors
We examined the theory of planned behavior (TPB) in predicting intentions to participate in group parenting education. One hundred and seventy-six parents (138 mothers and 38 fathers) with a child under 12 years completed TPB items assessing attitude, subjective norms, perceived behavioral control (PBC), and two additional social influence variables (self-identity and group norm). Regression analyses supported the TPB predictors of participation intentions with self-identity and group norm also significantly predicting intentions. These findings offer preliminary support for the TPB, along with additional sources of social influence, as a useful predictive model of participation in parenting education
Comparison of Methods for the Purification of Alpha-1 Acid Glycoprotein from Human Plasma
Alpha-1 acid glycoprotein (AGP) is a highly glycosylated, negatively charged plasma protein suggested to have anti-inflammatory and/or immunomodulatory activities. Purification of AGP could be simplified if methods that exploit its high solubility under chemically harsh conditions could be demonstrated to leave the protein in its native conformation. Procedures involving exposure of AGP to hot phenol or sulphosalicylic acid (SSA) were compared to solely chromatographic methods. Hot phenol-purified AGP was more rapidly cleared from mice in vivo following intravenous injection than chromatographically purified AGP. In contrast, SSA-purified AGP demonstrated an identical in vivo clearance profile and circular dichroism spectrum to chromatographically purified AGP. Similarly, no differences in susceptibility to enzymatic deglycosylation or reactivity with Sambucus nigra lectin were detected between AGP purified via the two methods. Incorporation of the SSA step in the purification scheme for AGP eliminated the need for a large (4 mL resin/mL of plasma) initial chromatographic step and simplified its purification without causing any detectable distortion in the conformation of the protein. Confirmation that this procedure is nondenaturing will simplify AGP purification and investigation of its possible biological roles in laboratory animals
In Vivo Clearance of Alpha-1 Acid Glycoprotein Is Influenced by the Extent of Its N-Linked Glycosylation and by Its Interaction with the Vessel Wall
Alpha-1 acid glycoprotein (AGP) is a highly glycosylated plasma protein that exerts vasoprotective effects. We hypothesized that AGP's N-linked glycans govern its rate of clearance from the circulation, and followed the disappearance of different forms of radiolabeled human AGP from the plasma of rabbits and mice. Enzymatic deglycosylation of human plasma-derived AGP (pdAGP) by Peptide: N-Glycosidase F yielded a mixture of differentially deglycosylated forms (PNGase-AGP), while the introduction of five Asn to Gln mutations in recombinant Pichia pastoris-derived AGP (rAGP-N(5)Q) eliminated N-linked glycosylation. PNGase-AGP was cleared from the rabbit circulation 9-fold, and rAGP-N(5)Q, 46-fold more rapidly than pdAGP, primarily via a renal route. Pichia pastoris-derived wild-type rAGP differed from pdAGP in expressing mannose-terminated glycans, and, like neuraminidase-treated pdAGP, was more rapidly removed from the rabbit circulation than rAGP-N(5)Q. Systemic hyaluronidase treatment of mice transiently decreased pdAGP clearance. AGP administration to mice reduced vascular binding of hyaluronic acid binding protein in the liver microcirculation and increased its plasma levels. Our results support a critical role of N-linked glycosylation of AGP in regulating its in vivo clearance and an influence of a hyaluronidase-sensitive component of the vessel wall on its transendothelial passage
Norm estimates of complex symmetric operators applied to quantum systems
This paper communicates recent results in theory of complex symmetric
operators and shows, through two non-trivial examples, their potential
usefulness in the study of Schr\"odinger operators. In particular, we propose a
formula for computing the norm of a compact complex symmetric operator. This
observation is applied to two concrete problems related to quantum mechanical
systems. First, we give sharp estimates on the exponential decay of the
resolvent and the single-particle density matrix for Schr\"odinger operators
with spectral gaps. Second, we provide new ways of evaluating the resolvent
norm for Schr\"odinger operators appearing in the complex scaling theory of
resonances
Resonance Lifetimes from Complex Densities
The ab-initio calculation of resonance lifetimes of metastable anions
challenges modern quantum-chemical methods. The exact lifetime of the
lowest-energy resonance is encoded into a complex "density" that can be
obtained via complex-coordinate scaling. We illustrate this with one-electron
examples and show how the lifetime can be extracted from the complex density in
much the same way as the ground-state energy of bound systems is extracted from
its ground-state density
Non-Equilibrium Dynamics in Two-Color, Few-Photon Dissociative Excitation and Ionization of D
D molecules, excited by linearly cross-polarized femtosecond extreme
ultraviolet (XUV) and near-infrared (NIR) light pulses, reveal highly
structured D ion fragment momenta and angular distributions that originate
from two different 4-step dissociative ionization pathways after four photon
absorption (1 XUV + 3 NIR). We show that, even for very low dissociation
kinetic energy release ~240~meV, specific electronic excitation pathways
can be identified and isolated in the final ion momentum distributions. With
the aid of {\it ab initio} electronic structure and time-dependent
Schr\"odinger equation calculations, angular momentum, energy, and parity
conservation are used to identify the excited neutral molecular states and
molecular orientations relative to the polarization vectors in these different
photoexcitation and dissociation sequences of the neutral D molecule and
its D cation. In one sequential photodissociation pathway, molecules
aligned along either of the two light polarization vectors are excluded, while
another pathway selects molecules aligned parallel to the light propagation
direction. The evolution of the nuclear wave packet on the intermediate \Bstate
electronic state of the neutral D molecule is also probed in real time.Comment: 11 pages including 6 figure
Noncommutative Differential Forms on the kappa-deformed Space
We construct a differential algebra of forms on the kappa-deformed space. For
a given realization of the noncommutative coordinates as formal power series in
the Weyl algebra we find an infinite family of one-forms and nilpotent exterior
derivatives. We derive explicit expressions for the exterior derivative and
one-forms in covariant and noncovariant realizations. We also introduce
higher-order forms and show that the exterior derivative satisfies the graded
Leibniz rule. The differential forms are generally not graded-commutative, but
they satisfy the graded Jacobi identity. We also consider the star-product of
classical differential forms. The star-product is well-defined if the
commutator between the noncommutative coordinates and one-forms is closed in
the space of one-forms alone. In addition, we show that in certain realizations
the exterior derivative acting on the star-product satisfies the undeformed
Leibniz rule.Comment: to appear in J. Phys. A: Math. Theo
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