12,533 research outputs found
ALTERNATIVE METHODS FOR DISTRIBUTING STATE AID TO LOCAL GOVERNMENTS IN NEW YORK
This paper simulates alternative distributions of general purpose state aid to local governments under different combinations of criteria: tax capacity, effort, and revenue needs. Revenue needs are based on Tobit estimates of the costs of providing average levels of 16 categories of services. Segmenting the sample into high and low population jurisdictions provided a more realistic set of cost estimates. Available revenues or capacity are determined by multiplying each jurisdiction's tax bases by standard tax rates. A Need-Capacity gap, the difference between needed revenues and available revenues, is used as a needs-based distribution strategy for general purpose aid. Finally an effort gap, based on above average tax efforts was added to the Need-Capacity gap to define a Need-Capacity-Effort strategy.Public Economics,
Many Body Methods and Effective Field Theory
In the framework of pionless nucleon-nucleon effective field theory we study
different approximation schemes for the nuclear many body problem. We consider,
in particular, ladder diagrams constructed from particle-particle, hole-hole,
and particle-hole pairs. We focus on the problem of finding a suitable starting
point for perturbative calculations near the unitary limit (k_Fa)->infinity and
(k_Fr)-> 0, where k_F is the Fermi momentum, a is the scattering length and r
is the effective range. We try to clarify the relationship between different
classes of diagrams and the large g and large D approximations, where g is the
fermion degeneracy and D is the number of space time dimensions. In the large D
limit we find that the energy per particle in the strongly interacting system
is 1/2 the result for free fermions.Comment: 23 pages, 8 figure
Measurement of the SOC State Specific Heat in ^4He
When a heat flux Q is applied downward through a sample of liquid 4He near the lambda transition, the helium self organizes such that the gradient in temperature matches the gravity induced gradient in Tlambda. All the helium in the sample is then at the same reduced temperature tSOC = ((T[sub SOC] - T[sub lambda])/T[sub lambda]) and the helium is said to be in the Self-Organized Critical (SOC) state. We have made preliminary measurements of the 4He SOC state specific heat, C[del]T(T(Q)). Despite having a cell height of 2.54 cm, our results show no difference between C[del]T and the zero-gravity 4He specific heat results of the Lambda Point Experiment (LPE) [J.A. Lipa et al., Phys. Rev. B, 68, 174518 (2003)] over the range 250 to 450 nK below the transition. There is no gravity rounding because the entire sample is at the same reduced temperature tSOC(Q). Closer to Tlambda the SOC specific heat falls slightly below LPE, reaching a maximum at approximately 50 nK below Tlambda, in agreement with theoretical predictions [R. Haussmann, Phys. Rev. B, 60, 12349 (1999)]
Crystallization and preliminary X-ray analysis of neoagarobiose hydrolase from Saccharophagus degradans 2-40
Many agarolytic bacteria degrade agar polysaccharide into the disaccharide unit neoagarobiose [O-3,6-anhydro-α-L-galactopyranosyl-(1→3)-D-galactose] using various β-agarases. Neoagarobiose hydrolase is an enzyme that acts on the α-1,3 linkage in neoagarobiose to yield D-galactose and 3,6-anhydro-L-galactose. This activity is essential in both the metabolism of agar by agarolytic bacteria and the production of fermentable sugars from agar biomass for bioenergy production. Neoagarobiose hydrolase from the marine bacterium Saccharophagus degradans 2-40 was overexpressed in Escherichia coli and crystallized in the monoclinic space group C2, with unit-cell parameters a = 129.83, b = 76.81, c = 90.11 Å, β = 101.86°. The crystals diffracted to 1.98 Å resolution and possibly contains two molecules in the asymmetric unit
CephBase: Testing Ideas for Cephalopod and Other Species-Level Databases
This report shares our experience of what worked and what did not while developing CephBase (www.cephbase.dal.ca). We share our triumphs and failures as well as our vision for the future to help and encourage those starting new database projects as well as outline ideas about collaboration between existing and yet to be developed databases. It also explains why we chose cephalopods and urges readers to share their enthusiasm for the groups of marine animals they investigate. Clearly, new Internet technologies offer a chance for substantial improvement in global distribution and sharing of information
Dispersive Elastodynamics of 1D Banded Materials and Structures: Design
Within periodic materials and structures, wave scattering and dispersion
occur across constituent material interfaces leading to a banded frequency
response. In an earlier paper, the elastodynamics of one-dimensional periodic
materials and finite structures comprising these materials were examined with
an emphasis on their frequency-dependent characteristics. In this work, a novel
design paradigm is presented whereby periodic unit cells are designed for
desired frequency band properties, and with appropriate scaling, these cells
are used as building blocks for forming fully periodic or partially periodic
structures with related dynamical characteristics. Through this multiscale
dispersive design methodology, which is hierarchical and integrated, structures
can be devised for effective vibration or shock isolation without needing to
employ dissipative damping mechanisms. The speed of energy propagation in a
designed structure can also be dictated through synthesis of the unit cells.
Case studies are presented to demonstrate the effectiveness of the methodology
for several applications. Results are given from sensitivity analyses that
indicate a high level of robustness to geometric variation.Comment: 33 text pages, 27 figure
Reversible, Opto-Mechanically Induced Spin-Switching in a Nanoribbon-Spiropyran Hybrid Material
It has recently been shown that electronic transport in zigzag graphene
nanoribbons becomes spin-polarized upon application of an electric field across
the nanoribbon width. However, the electric fields required to experimentally
induce this magnetic state are typically large and difficult to apply in
practice. Here, using both first-principles density functional theory (DFT) and
time-dependent DFT, we show that a new spiropyran-based, mechanochromic polymer
noncovalently deposited on a nanoribbon can collectively function as a dual
opto-mechanical switch for modulating its own spin-polarization. These
calculations demonstrate that upon mechanical stress or photoabsorption, the
spiropyran chromophore isomerizes from a closed-configuration ground-state to a
zwitterionic excited-state, resulting in a large change in dipole moment that
alters the electrostatic environment of the nanoribbon. We show that the
electronic spin-distribution in the nanoribbon-spiropyran hybrid material can
be reversibly modulated via noninvasive optical and mechanical stimuli without
the need for large external electric fields. Our results suggest that the
reversible spintronic properties inherent to the nanoribbon-spiropyran material
allow the possibility of using this hybrid structure as a resettable,
molecular-logic quantum sensor where opto-mechanical stimuli are used as inputs
and the spin-polarized current induced in the nanoribbon substrate is the
measured output.Comment: Accepted by Nanoscal
Experimental Analysis of Cross-Flow Grain Drying Systems in Deep Cylindrical Bins
Agricultural Engineerin
Evaluating Mediated Perception of Narrative Health Messages: The Perception of Narrative Performance Scale
Narrative media health messages have proven effective in preventing adolescents’ substance use but as yet few measures exist to assess perceptions of them. Without such a measure it is difficult to evaluate the role these messages play in health promotion or to differentiate them from other message forms. In response to this need, a study was conducted to evaluate the Perception of Narrative Performance Scale that assesses perceptions of narrative health messages. A sample of 1185 fifth graders in public schools at Phoenix, Arizona completed a questionnaire rating of two videos presenting narrative substance use prevention messages. Confirmatory factor analyses were computed to identify the factor structure of the scale. Consistent with prior studies, results suggest a 3 factor structure for the Perception of Narrative Performance Scale: interest, realism, and identification (with characters). In addition, a path analysis was performed to test the predictive power of the scale. The analysis shows that the scale proves useful in predicting intent to use substances. Finally, practical implications and limitations are discussed
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