9,608 research outputs found
An Investigation of Changes in Contributions of State Lotteries to Education Over Time
Arkansas is one of many states in this country that is experiencing an education funding crisis. Despite the fact that states have started taking more responsibility for the funding of their public schools since the mid-1950s, litigation over education funding has occurred in almost every state in the United States. Litigation in Arkansas began in the 1980s and continues today with the Lake View case. Several alternatives have been proposed to reform the state\u27s education system and its methods of funding, including school consolidation, raising taxes, and adopting an education-supporting lottery. Lotteries have become very popular revenue raising mechanisms in the United States since the 1960s. Supporters of lottery adoption claim that lotteries are significant revenue raisers for new and existing programs and that they are better than increasing taxes. Opponents of lottery adoption contend that lotteries are regressive, implicit taxes and that the revenues from lotteries are fungible and do not increase education funding. Data will be analyzed to determine whether lottery prize payout ratios have increased significantly over time, and whether changes in lottery prize payout ratios have had an impact on the money expended on public education. Based on this information and previous research, a recommendation will be made as to whether adopting an education-supporting lottery would be an effective and adequate way to help fund public education in the state of Arkansas
Characterisation of spatial network-like patterns from junctions' geometry
We propose a new method for quantitative characterization of spatial
network-like patterns with loops, such as surface fracture patterns, leaf vein
networks and patterns of urban streets. Such patterns are not well
characterized by purely topological estimators: also patterns that both look
different and result from different morphogenetic processes can have similar
topology. A local geometric cue -the angles formed by the different branches at
junctions- can complement topological information and allow to quantify the
large scale spatial coherence of the pattern. For patterns that grow over time,
such as fracture lines on the surface of ceramics, the rank assigned by our
method to each individual segment of the pattern approximates the order of
appearance of that segment. We apply the method to various network-like
patterns and we find a continuous but sharp dichotomy between two classes of
spatial networks: hierarchical and homogeneous. The first class results from a
sequential growth process and presents large scale organization, the latter
presents local, but not global organization.Comment: version 2, 14 page
Computing Fault Displacements from Surface Deformations
Simplex is a computer program that calculates locations and displacements of subterranean faults from data on Earth-surface deformations. The calculation involves inversion of a forward model (given a point source representing a fault, a forward model calculates the surface deformations) for displacements, and strains caused by a fault located in isotropic, elastic half-space. The inversion involves the use of nonlinear, multiparameter estimation techniques. The input surface-deformation data can be in multiple formats, with absolute or differential positioning. The input data can be derived from multiple sources, including interferometric synthetic-aperture radar, the Global Positioning System, and strain meters. Parameters can be constrained or free. Estimates can be calculated for single or multiple faults. Estimates of parameters are accompanied by reports of their covariances and uncertainties. Simplex has been tested extensively against forward models and against other means of inverting geodetic data and seismic observations. This wor
Radial velocities of RR Lyrae stars in and around NGC 6441
Detailed elemental abundance patterns of metal-poor ([Fe/H] ~ -1~dex) stars
in the Galactic bulge indicate that a number of them are consistent with
globular cluster (GC) stars and may be former members of dissolved GCs. This
would indicate that a few per cent of the Galactic bulge was built up from
destruction and/or evaporation of globular clusters. Here an attempt is made to
identify such presumptive stripped stars originating from the massive, inner
Galaxy globular cluster NGC~6441 using its rich RR Lyrae variable star (RRL)
population. We present radial velocities of forty RRLs centered on the globular
cluster NGC~6441. All of the 13 RRLs observed within the cluster tidal radius
have velocities consistent with cluster membership, with an average radial
velocity of 24 +- 5~km/s and a star-to-star scatter of 11~km/s. This includes
two new RRLs that were previously not associated with the cluster. Eight RRLs
with radial velocities consistent with cluster membership but up to three time
the distance from the tidal radius are also reported. These potential
extra-tidal RRLs also have exceptionally long periods, which is a curious
characteristic of the NGC~6441 RRL population that hosts RRLs with periods
longer than seen anywhere else in the Milky Way. As expected of stripped
cluster stars, most are inline with the cluster's orbit. Therefore, either the
tidal radius of NGC~6441 is underestimated and/or we are seeing dissolving
cluster stars stemming from NGC~6441 that are building up the old spheroidal
bulge.Comment: accepted to A
Simplex GPS and InSAR Inversion Software
Changes in the shape of the Earth's surface can be routinely measured with precisions better than centimeters. Processes below the surface often drive these changes and as a result, investigators require models with inversion methods to characterize the sources. Simplex inverts any combination of GPS (global positioning system), UAVSAR (uninhabited aerial vehicle synthetic aperture radar), and InSAR (interferometric synthetic aperture radar) data simultaneously for elastic response from fault and fluid motions. It can be used to solve for multiple faults and parameters, all of which can be specified or allowed to vary. The software can be used to study long-term tectonic motions and the faults responsible for those motions, or can be used to invert for co-seismic slip from earthquakes. Solutions involving estimation of fault motion and changes in fluid reservoirs such as magma or water are possible. Any arbitrary number of faults or parameters can be considered. Simplex specifically solves for any of location, geometry, fault slip, and expansion/contraction of a single or multiple faults. It inverts GPS and InSAR data for elastic dislocations in a half-space. Slip parameters include strike slip, dip slip, and tensile dislocations. It includes a map interface for both setting up the models and viewing the results. Results, including faults, and observed, computed, and residual displacements, are output in text format, a map interface, and can be exported to KML. The software interfaces with the QuakeTables database allowing a user to select existing fault parameters or data. Simplex can be accessed through the QuakeSim portal graphical user interface or run from a UNIX command line
Sunlight-mediated inactivation of health-relevant microorganisms in water: a review of mechanisms and modeling approaches.
Health-relevant microorganisms present in natural surface waters and engineered treatment systems that are exposed to sunlight can be inactivated by a complex set of interacting mechanisms. The net impact of sunlight depends on the solar spectral irradiance, the susceptibility of the specific microorganism to each mechanism, and the water quality; inactivation rates can vary by orders of magnitude depending on the organism and environmental conditions. Natural organic matter (NOM) has a large influence, as it can attenuate radiation and thus decrease inactivation by endogenous mechanisms. Simultaneously NOM sensitizes the formation of reactive intermediates that can damage microorganisms via exogenous mechanisms. To accurately predict inactivation and design engineered systems that enhance solar inactivation, it is necessary to model these processes, although some details are not yet sufficiently well understood. In this critical review, we summarize the photo-physics, -chemistry, and -biology that underpin sunlight-mediated inactivation, as well as the targets of damage and cellular responses to sunlight exposure. Viruses that are not susceptible to exogenous inactivation are only inactivated if UVB wavelengths (280-320 nm) are present, such as in very clear, open waters or in containers that are transparent to UVB. Bacteria are susceptible to slightly longer wavelengths. Some viruses and bacteria (especially Gram-positive) are susceptible to exogenous inactivation, which can be initiated by visible as well as UV wavelengths. We review approaches to model sunlight-mediated inactivation and illustrate how the environmental conditions can dramatically shift the inactivation rate of organisms. The implications of this mechanistic understanding of solar inactivation are discussed for a range of applications, including recreational water quality, natural treatment systems, solar disinfection of drinking water (SODIS), and enhanced inactivation via the use of sensitizers and photocatalysts. Finally, priorities for future research are identified that will further our understanding of the key role that sunlight disinfection plays in natural systems and the potential to enhance this process in engineered systems
A missing high-spin molecule in the family of cyano-bridged heptanuclear heterometal complexes, [(LCuII)6FeIII(CN)6]3+, and its CoIII and CrIII analogues, accompanied in the crystal by a novel octameric water cluster
Three isostructural cyano-bridged heptanuclear complexes,
[{CuII(saldmen)(H2O)}6{MIII(CN)6}](ClO4)38H2O (M = FeIII 2; CoIII, 3;
CrIII 4), have been obtained by reacting the binuclear copper(II) complex,
[Cu2(saldmen)2(mu-H2O)(H2O)2](ClO4)22H2O 1, with K3[Co(CN)6],
K4[Fe(CN)6], and, respectively, K3[Cr(CN)6] (Hsaldmen is the Schiff base
resulted from the condensation of salicylaldehyde with
N,N-dimethylethylenediamine). A unique octameric water cluster, with
bicyclo[2,2,2]octane-like structure, is sandwiched between the heptanuclear
cations in 2, 3 and 4. The cryomagnetic investigations of compounds 2 and 4
reveal ferromagnetic couplings of the central FeIII or CrIII ions with the CuII
ions (JCuFe = +0.87 cm-1, JCuCr = +30.4 cm-1). The intramolecular Cu-Cu
exchange interaction in 3, across the diamagnetic cobalt(III) ion, is -0.3
cm-1. The solid-state1H-NMR spectra of compounds 2 and 3 have been
investigated
Hyphenated LC-ICP-MS/ESI-MS identification of halogenated metabolites in South African marine ascidian extracts
Extracts of 13 species of marine ascidian collected in Algoa Bay were analyzed by LC-ICP-MS/ESI-MS. This technique allows
parallel analysis of the molecular species and the presence of certain elements. The LC-ICP-MS/ESI-MS technique was used to
target iodinated metabolites in this study. Three ascidian species afforded the known 3,5–diiodo-4-methoxyphenethylamine
(12), which was confirmedby the isolation of this metabolite fromAplidium monile.MS also suggested the presence of theknown
3,5–dibromo-4-methoxyphenethylamine (10) and the new 3-bromo-5–iodo-4-methoxyphenethylamine (11) in the A. monile
extract. The presence of the known 3,5-dibromotetramethyltyrosine (21) and the new 3-iodotetramethyltyrosine (23) in extracts
of an unidentified Didemnum species was similarly proposed from MS evidence. This is the first report of the occurrence of
iodinated metabolites in South African marine invertebrates.IS
Whey- vs Casein-Based Enteral Formula and Gastrointestinal Function in Children With Cerebral Palsy.
Objectives: Children with severe cerebral palsy (CP) commonly have gastrointestinal (GI) dysfunction. Whey-based enteral formulas have been postulated to reduce gastroesophageal reflux (GOR) and accelerate gastric emptying (GE). The authors investigated whether whey-based (vs casein-based) enteral formulas reduce GOR and accelerate GE in children who have severe CP with a gastrostomy and fundoplication.
Methods: Thirteen children received a casein-based formula for 1 week and either a 50% whey whole protein (50% WWP) or a 100% whey partially hydrolyzed protein (100% WPHP) formula for 1 week. Reflux episodes, gastric half-emptying time (GE t1/2), and reported pain and GI symptoms were measured.
Results: Whey formulas emptied significantly faster than casein (median [interquartile range (IQR)] GE t1/2, 33.9 [25.3-166.2] min vs 56.6 [46-191] min; P = .033). Reflux parameters were unchanged. GI symptoms were lower in children who received 50% WWP (visual analog symptom score, median [IQR], 0[0-11.8]) vs 100% WPHP (13.0 [2.5-24.8]) (P = .035).
Conclusion: This pilot study shows that in children who have severe CP with a gastrostomy and fundoplication, GE of the whey-based enteral formula is significantly faster than casein. The acceleration in GE does not alter GOR frequency, and there appears to be no effect of whey vs casein in reducing acid, nonacid, and total reflux episodes. The results indicate that enteral formula selection may be particularly important for children with severe CP and delayed GE. (JPEN J Parenter Enteral Nutr. 2012;36:118S-123S
Progress in Computational Simulation of Earthquakes
GeoFEST(P) is a computer program written for use in the QuakeSim project, which is devoted to development and improvement of means of computational simulation of earthquakes. GeoFEST(P) models interacting earthquake fault systems from the fault-nucleation to the tectonic scale. The development of GeoFEST( P) has involved coupling of two programs: GeoFEST and the Pyramid Adaptive Mesh Refinement Library. GeoFEST is a message-passing-interface-parallel code that utilizes a finite-element technique to simulate evolution of stress, fault slip, and plastic/elastic deformation in realistic materials like those of faulted regions of the crust of the Earth. The products of such simulations are synthetic observable time-dependent surface deformations on time scales from days to decades. Pyramid Adaptive Mesh Refinement Library is a software library that facilitates the generation of computational meshes for solving physical problems. In an application of GeoFEST(P), a computational grid can be dynamically adapted as stress grows on a fault. Simulations on workstations using a few tens of thousands of stress and displacement finite elements can now be expanded to multiple millions of elements with greater than 98-percent scaled efficiency on over many hundreds of parallel processors (see figure)
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