The Meaning of Molecular Connectivity: A Bimolecular Accessibility Model

The simple molecular connectivity indices are analysed for the information in the bond terms. It is found that these terms reflect the relative accessibility of each bond to encounter other bonds of the same molecule in a milieu. The total possibility of each molecule to encounter another molecule in a bimolecular interaction is found to be the molecular connectivity index for that molecule. The molecular connectivity indices are interpreted to be the bimolecular interaction possibilities of a molecule in a milieu

Metric System for Evaluating Off-site Mitigation for Ecosystem Services and Wildlife Habitat in Sagebrush Ecosystems

A fundamental concept of mitigation is that it is possible to compensate for impacts to ecosystem services at one site (the impact site) by replacing or increasing the same services at another site (the mitigation site). A challenge in the use of off-site mitigation is assuring that ecosystem services, including wildlife habitat, produced by off-site mitigation are commensurate with on-site impacts. Recent increases in energy developments within the sagebrush biome have raised concerns about impacts associated with these activities and efforts to mitigate those impacts. To help address these concerns, we developed a metric system to quantify impact losses and mitigation benefits based on a combination of NRCS Ecological Sites, existing vegetation conditions, and habitat assessment conducted at the landscape level for sagebrush-associated wildlife species. Changes to vegetation conditions within sagebrush ecosystems produced by on-the-ground mitigation treatments or by impacts are quantified based on comparison to a reference standard developed from the Ecological Site Description for the specific plant communities associated with either the mitigation or impact site. Wildlife benefits are also evaluated at a landscape scale using models that quantify the gains or losses in habitat quality associated with the mitigation or development activities. This metric system provides a standardized way of quantifying gains and losses of ecosystem services and wildlife habitat associated with impacts and mitigation which will help to ensure that gains associated with mitigation activities are commensurate with losses resulting from development

An Assessment of a 15 vs. 30 Second Recovery Period on Vertical Jump Performance

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Assessing the Impact of a Governed Focal Point on Broad Jump Performance in Collegiate Females

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Immunofluorescent Localization of RuBPCase in Degraded C\u3csub\u3e4\u3c/sub\u3e Grass Tissue

Digestion-resistant tissues found in C4 grasses may allow soluble protein to escape rumen degradation. The objective of this study was to use immunofluorescent localization to follow loss of ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBPCase) from switchgrass (Panicum virgatum L.) and big bluestem (Andropogon gerardii Vitman) parenchyma bundle sheath cells (BSC) during rumen degradation. Fluorescent signal was observed from switchgrass and big bluestem BSC through 24 and 16 h in situ digestion, respectively, and from BSC associated with both intact tissue fragments, and isolated vascular bundles in omasal digesta and fecal material from steers (Bos tarus L.) grazing switchgrass. Immunofluorescent localization demonstrated that in certain C4 grasses (i) parenchyma BSC can protect RuBPCase from degradation through 24-h in situ incubation, (ii) BSC containing RuBPCase can exit the rumen prior to degradation, and (iii) protein protected by BSC can escape degradation in the whole gastrointestinal tract and be excreted

Nuclear Reaction Rates in a Plasma

The problem of determining the effects of the surrounding plasma on nuclear reaction rates in stars is formulated ab initio, using the techniques of quantum statistical mechanics. We derive a result that expresses the complete effects of Coulomb barrier penetration and of the influence of the surrounding plasma in terms of matrix elements of well defined operators. We find that possible "dynamical screening" effects that have been discussed in the literature are absent. The form of our results suggests that an approach that relies on numerical calculations of the correlation functions in a classical Coulomb gas, followed by construction of an effective two body potential and a quantum barrier penetration calculation, will miss physics that is as important as the physics that it includes.Comment: 66 pages, revtex, Errors Fixed, Explanation Adde

The Influence of Specimen Thickness on the High Temperature Corrosion Behavior of CMSX-4 during Thermal-Cycling Exposure

CMSX-4 is a single-crystalline Ni-base superalloy designed to be used at very high temperatures and high mechanical loadings. Its excellent corrosion resistance is due to external alumina-scale formation, which however can become less protective under thermal-cycling conditions. The metallic substrate in combination with its superficial oxide scale has to be considered as a composite suffering high stresses. Factors like different coefficients of thermal expansion between oxide and substrate during temperature changes or growing stresses affect the integrity of the oxide scale. This must also be strongly influenced by the thickness of the oxide scale and the substrate as well as the ability to relief such stresses, e.g., by creep deformation. In order to quantify these effects, thin-walled specimens of different thickness (t = 100500 lm) were prepared. Discontinuous measurements of their mass changes were carried out under thermal-cycling conditions at a hot dwell temperature of 1100 C up to 300 thermal cycles. Thin-walled specimens revealed a much lower oxide-spallation rate compared to thick-walled specimens, while thinwalled specimens might show a premature depletion of scale-forming elements. In order to determine which of these competetive factor is more detrimental in terms of a component’s lifetime, the degradation by internal precipitation was studied using scanning electron microscopy (SEM) in combination with energy-dispersive X-ray spectroscopy (EDS). Additionally, a recently developed statistical spallation model was applied to experimental data [D. Poquillon and D. Monceau, Oxidation of Metals, 59, 409–431 (2003)]. The model describes the overall mass change by oxide scale spallation during thermal cycling exposure and is a useful simulation tool for oxide scale spallation processes accounting for variations in the specimen geometry. The evolution of the net-mass change vs. the number of thermal cycles seems to be strongly dependent on the sample thickness

The rarity of terrestrial gamma-ray flashes

We report on the first search for Terrestrial Gamma-ray Flashes (TGFs) from altitudes where they are thought to be produced. The Airborne Detector for Energetic Lightning Emissions (ADELE), an array of gamma-ray detectors, was flown near the tops of Florida thunderstorms in August/September 2009. The plane passed within 10 km horizontal distance of 1213 lightning discharges and only once detected a TGF. If these discharges had produced TGFs of the same intensity as those seen from space, every one should have been seen by ADELE. Separate and significant nondetections are established for intracloud lightning, negative cloud-to-ground lightning, and narrow bipolar events. We conclude that TGFs are not a primary triggering mechanism for lightning. We estimate the TGF-to-flash ratio to be on the order of 10^(−2) to 10^(−3) and show that TGF intensities cannot follow the well-known power-law distribution seen in earthquakes and solar flares, due to our limits on the presence of faint events

Nonmonotonous Magnetic Field Dependence and Scaling of the Thermal Conductivity for Superconductors with Nodes of the Order Parameter

We show that there is a new mechanism for nonmonotonous behavior of magnetic field dependence of the electronic thermal conductivity of clean superconductors with nodes of the order parameter on the Fermi surface. In particular, for unitary scatterers the nonmonotony of relaxation time takes place. Contribution from the intervortex space turns out to be essential for this effect even at low temperatures. Our results are in a qualitative agreement with recent experimental data for superconducting UPt_3. For E_{2u}-type of pairing we find approximately the scaling of the thermal conductivity in clean limit with a single parameter x=T/T_c\sqrt{B_{c2}/B} at low fields and low temperatures, as well as weak low-temperature dependence of the anisotropy ratio K_{zz}/K_{yy} in zero field. For E_{1g}-type of pairing deviations from the scaling are more noticeable and the anisotropy ratio is essentially temperature dependent.Comment: 37 pages, 8 Postscript figures, REVTE

Convective instability of 3-D fluid-saturated geological fault zones heated from below

We conduct a theoretical analysis to investigate the convective instability of 3-D fluid-saturated geological fault zones when they are heated uniformly from below. In particular, we have derived exact analytical solutions for the critical Rayleigh numbers of different convective flow structures. Using these critical Rayleigh numbers, three interesting convective flow structures have been identified in a geological fault zone system. It has been recognized that the critical Rayleigh numbers of the system have a minimum value only for the fault zone of infinite length, in which the corresponding convective flow structure is a 2-D slender-circle flow. However, if the length of the fault zone is finite, the convective flow in the system must be 3-D. Even if the length of the fault zone is infinite, since the minimum critical Rayleigh number for the 2-D slender-circle flow structure is so close to that for the 3-D convective flow structure, the system may have almost the same chance to pick up the 3-D convective flow structures. Also, because the convection modes are so close for the 3-D convective flow structures, the convective flow may evolve into the 3-D finger-like structures, especially for the case of the fault thickness to height ratio approaching zero. This understanding demonstrates the beautiful aspects of the present analytical solution for the convective instability of 3-D geological fault zones, because the present analytical solution is valid for any value of the ratio of the fault height to thickness. Using the present analytical solution, the conditions, under which different convective flow structures may take place, can be easily determined