Analysis of data systems requirements for global crop production forecasting in the 1985 time frame

Data systems concepts that would be needed to implement the objective of the global crop production forecasting in an orderly transition from experimental to operational status in the 1985 time frame were examined. Information needs of users were converted into data system requirements, and the influence of these requirements on the formulation of a conceptual data system was analyzed. Any potential problem areas in meeting these data system requirements were identified in an iterative process

UHF and VHF radar observations of thunderstorms

A study of thunderstorms was made in the Summer of 1985 with the 430-MHz and 50-MHz radars at the Arecibo Observatory in Puerto Rico. Both radars use the 300-meter dish, which gives a beam width of less than 2 degrees even at these long wavelengths. Though the radars are steerable, only vertical beams were used in this experiment. The height resolution was 300 and 150 meters for the UHF and VHF, respectively. Lightning echoes, as well as returns from precipitation and clear-air turbulence were detected with both wavelengths. Large increases in the returned power were found to be coincident with increasing downward vertical velocities at UHF, whereas at VHF the total power returned was relatively constant during the life of a storm. This was attributed to the fact that the VHF is more sensitive to scattering from the turbulence-induced inhomogeneities in the refractive index and less sensitive to scatter from precipitation particles. On occasion, the shape of the Doppler spectra was observed to change with the occurrence of a lightning discharge in the pulse volume. Though the total power and mean reflectivity weighted Doppler velocity changed little during these events, the power is Doppler frequency bins near that corresponding to the updraft did increase substantially within a fraction of a second after a discharge was detected in the beam. This suggests some interaction between precipitation and lightning

C32, A Young Star Cluster in IC 1613

The Local Group irregular galaxy IC 1613 has remained an enigma for many years because of its apparent lack of star clusters. We report the successful search for clusters among several of the candidate objects identified many years ago on photographic plates. We have used a single HST WFPC2 pointing and a series of images obtained with the WIYN telescope under exceptional seeing conditions, examining a total of 23 of the previously published candidates. All but six of these objects were found to be either asterisms or background galaxies. Five of the six remaining candidates possibly are small, sparse clusters and the sixth, C32, is an obvious cluster. It is a compact, young object, with an age of less than 10 million years and a total absolute magnitude of M_V = -5.78+/-0.16 within a radius of 13 pc.Comment: 5 pages, 5 figures, to be published in the May 2000 issue of the PAS

Instantaneous Pair Theory for High-Frequency Vibrational Energy Relaxation in Fluids

Notwithstanding the long and distinguished history of studies of vibrational energy relaxation, exactly how it is that high frequency vibrations manage to relax in a liquid remains somewhat of a mystery. Both experimental and theoretical approaches seem to say that there is a natural frequency range associated with intermolecular motions in liquids, typically spanning no more than a few hundred cm^{-1}. Landau-Teller-like theories explain how a solvent can absorb any vibrational energy within this "band", but how is it that molecules can rid themselves of superfluous vibrational energies significantly in excess of these values? We develop a theory for such processes based on the idea that the crucial liquid motions are those that most rapidly modulate the force on the vibrating coordinate -- and that by far the most important of these motions are those involving what we have called the mutual nearest neighbors of the vibrating solute. Specifically, we suggest that whenever there is a single solvent molecule sufficiently close to the solute that the solvent and solute are each other's nearest neighbors, then the instantaneous scattering dynamics of the solute-solvent pair alone suffices to explain the high frequency relaxation. The many-body features of the liquid only appear in the guise of a purely equilibrium problem, that of finding the likelihood of particularly effective solvent arrangements around the solute. These results are tested numerically on model diatomic solutes dissolved in atomic fluids (including the experimentally and theoretically interesting case of I_2 in Xe). The instantaneous pair theory leads to results in quantitative agreement with those obtained from far more laborious exact molecular dynamics simulations.Comment: 55 pages, 6 figures Scheduled to appear in J. Chem. Phys., Jan, 199

Balls, Strikes, and Norms: Rule Violations and Normative Rules Among Baseball Umpires

This study investigated the use of normative rules by baseball umpires. Normative rules are informal standards of conduct that deviate from the official rules of sport. Sixteen umpires, 25 coaches, and 27 baseball players defined the official upper and lower boundaries of the strike zone, marked these official boundaries on a Strike Zone Form, and marked where they actually call, or believe umpires call, the boundaries. Umpires were significantly more knowledgeable about rules than players were. Umpires reported setting the upper boundary of the strike zone significantly lower (an average of 2.64 inches) than the official rule specifies. Coaches and players reported that umpires lower the boundaries, but players overestimated how much umpires deviate from the rule-book boundaries. Results suggest that umpires consciously violate official rules. The ethical implications of these findings are discussed

Judgment Bias in Baseball Umpires First Base Calls: A Computer Simulation

Tested 39 baseball umpires and 39 undergraduates, using a computer simulation of 1st-base calls to determine the role of the prior entry phenomenon in close plays. Because umpires are directed to focus their attention on an auditory stimulus (ball hitting the glove), they may experience prior entry of the auditory stimulus, resulting in safe runners being called out. There were more errors when runners were just safe and safe because of a tie than when runners were just out, indicating that prior entry occurred in the simulations. This was more pronounced among umpires than controls

A Semiconductor Nanowire-Based Superconducting Qubit

We introduce a hybrid qubit based on a semiconductor nanowire with an epitaxially grown superconductor layer. Josephson energy of the transmon-like device ("gatemon") is controlled by an electrostatic gate that depletes carriers in a semiconducting weak link region. Strong coupling to an on-chip microwave cavity and coherent qubit control via gate voltage pulses is demonstrated, yielding reasonably long relaxation times (0.8 {\mu}s) and dephasing times (1 {\mu}s), exceeding gate operation times by two orders of magnitude, in these first-generation devices. Because qubit control relies on voltages rather than fluxes, dissipation in resistive control lines is reduced, screening reduces crosstalk, and the absence of flux control allows operation in a magnetic field, relevant for topological quantum information

Long-term stability and properties of zirconia ceramics for heavy duty diesel engine components

Physical, mechanical, and thermal properties of commercially available transformation-toughened zirconia are measured. Behavior is related to the material microstructure and phase assemblage. The stability of the materials is assessed after long-term exposure appropriate for diesel engine application. Properties measured included flexure strength, elastic modulus, fracture toughness, creep, thermal shock, thermal expansion, internal friction, and thermal diffusivity. Stability is assessed by measuring the residual property after 1000 hr/1000C static exposure. Additionally static fatigue and thermal fatigue testing is performed. Both yttria-stabilized and magnesia-stabilized materials are compared and contrasted. The major limitations of these materials are short term loss of properties with increasing temperature as the metastable tetragonal phase becomes more stable. Fine grain yttria-stabilized material (TZP) is higher strength and has a more stable microstructure with respect to overaging phenomena. The long-term limitation of Y-TZP is excessive creep deformation. Magnesia-stabilized PSZ has relatively poor stability at elevated temperature. Overaging, decomposition, and/or destabilization effects are observed. The major limitation of Mg-PSZ is controlling unwanted phase changes at elevated temperature

Voltage-Controlled Superconducting Quantum Bus

We demonstrate the ability of an epitaxial semiconductor-superconductor nanowire to serve as a field-effect switch to tune a superconducting cavity. Two superconducting gatemon qubits are coupled to the cavity, which acts as a quantum bus. Using a gate voltage to control the superconducting switch yields up to a factor of 8 change in qubit-qubit coupling between the on and off states without detrimental effect on qubit coherence. High-bandwidth operation of the coupling switch on nanosecond timescales degrades qubit coherence

Generalized multiresolution analyses with given multiplicity functions

Generalized multiresolution analyses are increasing sequences of subspaces of a Hilbert space \H that fail to be multiresolution analyses in the sense of wavelet theory because the core subspace does not have an orthonormal basis generated by a fixed scaling function. Previous authors have studied a multiplicity function $m$ which, loosely speaking, measures the failure of the GMRA to be an MRA. When the Hilbert space \H is $L^2(\mathbb R^n)$, the possible multiplicity functions have been characterized by Baggett and Merrill. Here we start with a function $m$ satisfying a consistency condition which is known to be necessary, and build a GMRA in an abstract Hilbert space with multiplicity function $m$.Comment: 16 pages including bibliograph