Improved Resolution from Double Constant-Time Evolution of 3D and 4D Triple-Resonance Experiments

Triple-resonance NMR experiments are nearly essential for performing backbone assignments of proteins larger than 15 kDa. Our work extends the double constant-time (2CT) evolution scheme to triple-resonance 3D and 4D experiments. The modifications needed to accomplish 2CT evolution in triple resonance experiments are straight forward, are completely general, and consequently, will yield increased resolution for all out-and-back experiments. We expect that the increased resolution of experiments presented here will be useful in the study of larger proteins (>30 kDa) and in the study of highly helical proteins where¹HN,¹⁵N, and¹³C dimensions are poorly dispersed.     

Intensity-reversal in the donor bound exciton luminescence of GaAs

A self-reversal model is presented to explain the luminescence dependence of the donor bound exciton intensity. The line broadening mechanism is attributed to rotational interaction with non-rigid rotator states. Line reversal results from absorption by non-broadened states near the crystal surface. The absence of a similar excitation intensity dependence for acceptor bound excitons is explained.     

The evaluation identification in function spaces

A study is made of the natural function which maps each point x of a space X to the evaluation function e_x:Y^x→Y defined by $\text{e}{}_{\mathrm{x}}\text{(?)=?(x)}$. A consequence of the results is that βX and υX can both be considered as subspaces of spaces of continous functions from appropriate domain spaces into I or R, respectively.     

Connection formulae for Painlevé V functions : II. The δ function Bose gas problem

We continue our study of those Painlevé V equations which admit a one-parameter family of solutions analytic at the origin and solve the global problem of connecting the 2-parameter expansion about t = 0 with the 2-parameter expansion valid for t → ± i∞. A special case of our results is applied to the study of the one-particle reduced density matrix of the one-dimensional gas of impenetrable bosons. We also use our results to obtain a 2-parameter connection formula for a class of Painlevé III functions.     

Temperature dependence in the Schumann-Runge photoabsorption continuum of oxygen

The photoabsorption cross section in the Schumann-Runge continuum of oxygen has been measured with high precision over the wavelength region 140–174 nm at temperatures in the range 295–575 K. Models for the upper state potential and the electronic transition moment were used in the calculation of the cross section and its temperature dependence. By comparing this theoretical cross section with measured values, curves for the upper state potential and the transition moment in the continuum region have been obtained independently for the first time.     

Rotational variation of predissociation linewidths for the Schumann-Runge bands of molecular oxygen

Predissociation linewidths are presented as a function of rotation for the (3-0)-(14-0) Schumann- Runge bands of molecular oxygen. While there may be a slight tendency overall for the linewidths to increase with rotation, it is shown that previous assumptions of linewidths constant with rotation are generally valid within the experimental error for the range of rotation studied, N_n ? 21. There is no evidence for the sudden increase in linewidth with rotation reported elsewhere.     

Experimentally determined oscillator strengths and linewidths for the Schumann-Runge band system of molecular oxygen—I. The (6-0)–(14-0) bands

Experimental oscillator strengths and predissociated linewidths have been measured at room temperature for the (6-0)–(14-0) Schumann-Runge bands of molecular oxygen using the Adelaide 6 m vacuum u.v. monochromator operated at a resolution of about 0.06 Å. Photoelectric detectors were used to measure the u.v. absorption at two different gas pressures for 138 groups of rotational lines distributed throughout the (6-0)–(14-0) bands and the resulting data were interpreted using an equivalent width type of analysis. Experimental measurements of the variation with N″ of the oscillator strengths within each band have been obtained for the first time. Measured oscillator strengths are found to be somwhat higher in general than previously reported values with a slightly faster decrease as N″ increases than is predicted theoretically. The mean predissociated linewidths obtained for each band show a smooth variation with v′, agreeing well with other results for v′=12?14 and lying between previously reported experimental and theoretical values for v′=6?9. The present work provides results which can be used to construct highly accurate synthetic absorption profiles for studies of the atmospheric absorption of u.v. radiation by the Schumann-Runge bands.     

Networks, dynamics, and modularity

The identification of general principles relating structure to dynamics has been a major goal in the study of complex networks. We propose that the special case of linear network dynamics provides a natural framework within which a number of interesting yet tractable problems can be defined. We report the emergence of modularity and hierarchical organization in evolved networks supporting asymptotically stable linear dynamics. Numerical experiments demonstrate that linear stability benefits from the presence of a hierarchy of modules and that this architecture improves the robustness of network stability to random perturbations in network structure. This work illustrates an approach to network science which is simultaneously structural and dynamical in nature.