14,866 research outputs found
The New Governance and the Tools of Public Action: An Introduction
A fundamental re-thinking is currently underway throughout the world about how to cope with public problems. Stimulated by popular frustrations with the cost and effectiveness of government programs and by a new-found faith in liberal economic theories, serious questions are being raised about the capabilities, and even the motivations, of public-sector institutions. This type of questioning has spread beyond American political discourse to other parts of the world. Underlying much of this reform surge is a set of theories that portrays government agencies as tightly structured hierarchies insulated from market forces and from effective citizen pressure and therefore free to serve the personal and institutional interests of bureaucrats instead. The heart of this revolution has been a fundamental transformation not just in the scope and scale of government action, but in its basic forms. Instead of relying exclusively on government to solve public problems, a host of other actors is being mobilized as well, sometimes are their own initiative but often in complex partnerships with the state
On Balazard, Saias, and Yor's equivalence to the Riemann Hypothesis
Balazard, Saias, and Yor proved that the Riemann Hypothesis is equivalent to
a certain weighted integral of the logarithm of the Riemann zeta-function along
the critical line equaling zero. Assuming the Riemann Hypothesis, we
investigate the rate at which a truncated version of this integral tends to
zero, answering a question of Borwein, Bradley, and Crandall and disproving a
conjecture of the same authors. A simple modification of our techniques gives a
new proof of a classical Omega theorem for the function S(t) in the theory of
the Riemann zeta-function.Comment: 11 page
Volunteering in Cross-National Perspective: Initial Comparisons
Anheier and Salamon shed some light on volunteering in different parts of the world by exploring the conceptions and patterns of voluntary action cross-nationally. As a cultural and economic phenomenon, volunteering is part of the way societies are organized, how they allocate social responsibilities, and how much engagement and participation they expect from citizens
Photoinduced Removal of Nifedipine Reveals Mechanisms of Calcium Antagonist Action on Single Heart Cells
The currents through voltage-activated calcium channels in heart cell membranes are suppressed by dihydropyridine calcium antagonists such as nifedipine. Nifedipine is photolabile, and the reduction of current amplitude by this drug can be reversed within a few milliseconds after a 1-ms light flash. The blockade by nifedipine and its removal by flashes were studied in isolated myocytes from neonatal rat heart using the whole-cell clamp method. The results suggest that nifedipine interacts with closed, open, and inactivated calcium channels. It is likely that at the normal resting potential of cardiac cells, the suppression of current amplitude arises because nifedipine binds to and stabilizes channels in the resting, closed state. Inhibition is enhanced at depolarized membrane potentials, where interaction with inactivated channels may also become important. Additional block of open channels is suggested when currents are carried by Ba^(2+) but is not indicated with Ca^(2+) currents. Numerical simulations reproduce the experimental observations with molecular dissociation constants on the order of 10^(-7) M for closed and open channels and 10^(-8) M for inactivated channels
High spatial resolution studies of galaxies in the far IR: Observations with the KAO, and the promise of SOFIA
NASA, in collaboration with the West German Science Ministry (BMFT), plans a larger airborne telescope as a successor to the Kuipper Airborne Observatory (KAO) that will achieve these goals. The Stratospheric Observatory for Infrared Astronomy (SOFIA) is entering the final stages of Phase B review with targeted new start early in the next decade. SOFIA is a 2.7 m diameter telescope that is carried in a Boeing 747SP. In addition to having 3 times the spatial resolution of the KAO, and 10 times the light gathering power, it will incorporate improvements over the KAO in lower optical emissivity and better telescope tracking stability. The thin primary mirror will equilibrate quickly to ambient temperature at an altitude which, accompanied by airflow improvements across the telescope cavity, will result in better image quality. The sensitivity of SOFIA will allow us to see a large number of typical bright galactic HII regions in local group galaxies. The spatial resolution of 8 seconds (full width half maximum Airy disk) at 100 microns will allow these regions to be measured independently, if they are distributed similarly to those in our own galaxy. At this spatial resolution, the disks of normal galaxies will be easily resolved out to distances of several hundred Mpc. This portion of space includes many of the superluminous galaxies discovered by the Infrared Astronomy Satellite (IRAS), and this spatial scale is relevant for studies of the morphology of regions of interaction among the majority of these galaxies that are members of colliding pairs
Second OH Overtone Excitation And Statistical Dissociation Dynamics Of Peroxynitrous Acid
The second OH overtone transition of the trans-perp conformer of peroxynitrous acid (tp-HOONO) is identified using infrared action spectroscopy. HOONO is produced by the recombination of photolytically generated OH and NO(2) radicals, and then cooled in a pulsed supersonic expansion. The second overtone transition is assigned to tp-HOONO based on its vibrational frequency (10 195.3 cm(-1)) and rotational band contour, which are in accord with theoretical predictions and previous observations of the first overtone transition. The transition dipole moment associated with the overtone transition is rotated considerably from the OH bond axis, as evident from its hybrid band composition, indicating substantial charge redistribution upon OH stretch excitation. The overtone band exhibits homogeneous line broadening that is attributed to intramolecular vibrational redistribution, arising from the coupling of the initially excited OH stretch to other modes that ultimately lead to dissociation. The quantum state distributions of the OH X (2)Pi (nu=0) products following first and second OH overtone excitation of tp-HOONO are found to be statistical by comparison with three commonly used statistical models. The product state distributions are principally determined by the tp-HOONO binding energy of 16.2(1) kcal mol(-1). Only a small fraction of the OH products are produced in nu=1 following the second overtone excitation, consistent with statistical predictions
Nonadiabatic Electronic Interactions In The Ion-Pair States Of NelCl
Nonadiabatic interactions in the NeIC1 van der Waals complex have been explored in the lowest energy triad of IC1 ion-pair states (approximately 39 000 cm-1). Dispersed fluorescence measurements reveal emission characteristic of multiple ion-pair electronic states, with the relative contributions from the E(O+ ), beta(1), and D\u27(2) states changing with the initial IC1 vibrational excitation (v(IC1)). Emission directly from NeIC1 (v(IC1) = O) complexes indicates that the initially prepared NeIC1 levels have mixed electronic character and that the IC1 electronic parentage changes with the initial van der Waals vibrational level selected. NeIC1 complexes prepared with 1-4 quanta of IC1 stretch undergo rapid vibrational predissociation with a strong propensity for DELTA-V(IC1) = - 1 relaxation. The electronic state(s) populated in the IC1 fragments differ from the mixed electronic character of the initially prepared level, demonstrating that vibrational predissociation is accompanied by nonadiabatic electronic state changing processes. The observed final state selectivity may be attributed to the relative strength of the nonadiabatic couplings between the initial NeIC1 bound state and the final IC1 states or a momentum gap rationale based on the overlap between the NeIC1 bound state wave function and the highly oscillatory continuum wave function of the separating fragments
Cooling a single atom in an optical tweezer to its quantum ground state
We report cooling of a single neutral atom to its three-dimensional
vibrational ground state in an optical tweezer. After employing Raman sideband
cooling for tens of milliseconds, we measure via sideband spectroscopy a
three-dimensional ground-state occupation of ~90%. We further observe coherent
control of the spin and motional state of the trapped atom. Our demonstration
shows that an optical tweezer, formed simply by a tightly focused beam of
light, creates sufficient confinement for efficient sideband cooling. This
source of ground-state neutral atoms will be instrumental in numerous quantum
simulation and logic applications that require a versatile platform for storing
and manipulating ultracold single neutral atoms. For example, these results
will improve current optical tweezer experiments studying atom-photon coupling
and Rydberg quantum logic gates, and could provide new opportunities such as
rapid production of single dipolar molecules or quantum simulation in tweezer
arrays.Comment: Updated intro, titl
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