790 research outputs found
Methods for Estimating Economic Damages from Environmental Contamination
While significant attention has been given to the decrease in property values associated with environmental contamination (i.e., stigma effects), little attention has been given to the stigma impacts on the local community as a whole. In addition, most estimates of stigma damages have been performed within a community, using distance from contamination or comparing contamination and non contamination areas in the community. In this article we determine stigma damages by analyzing property values in comparable communities and develop the rationale for estimating the community impact associated with environmental contamination that extends beyond the impact on individual property owners. These impacts were estimated for the environmental contamination from zinc smelting in the municipality of Blackwell, Oklahoma. The impacts were measured in terms of lost ad valorem tax revenue using hedonic pricing and average treatment effects.environmental damages, environmental contamination, Environmental Economics and Policy, Q51,
The Zieschang-McCool method for generating algebraic mapping-class groups
Let g and p be non-negative integers.
Let A(g,p) denote the group consisting of all those automorphisms of the free
group on {t_1,...,t_p, x_1,...,x_g, y_1,...y_g} which fix the element
t_1t_2...t_p[x_1,y_1]...[x_g,y_g] and permute the set of conjugacy classes
{[t_1],....,[t_p]}. Labru\`ere and Paris, building on work of Artin, Magnus,
Dehn, Nielsen, Lickorish, Zieschang, Birman, Humphries, and others, showed that
A(g,p) is generated by a set that is called the ADLH set. We use methods of
Zieschang and McCool to give a self-contained, algebraic proof of this result.
Labru\`ere and Paris also gave defining relations for the ADLH set in A(g,p);
we do not know an algebraic proof of this for g > 1. Consider an orientable
surface S(g,p) of genus g with p punctures, such that (g,p) is not (0,0) or
(0,1). The algebraic mapping-class group of S(g,p), denoted M(g,p), is defined
as the group of all those outer automorphisms of the one-relator group with
generating set {t_1,...,t_p, x_1,...,x_g, y_1,...y_g} and relator
t_1t_2...t_p[x_1,y_1]...[x_g,y_g] which permute the set of conjugacy classes
{[t_1],....,[t_p]}. It now follows from a result of Nielsen that M(g,p) is
generated by the image of the ADLH set together with a reflection. This gives a
new way of seeing that M(g,p) equals the (topological) mapping-class group of
S(g,p), along lines suggested by Magnus, Karrass, and Solitar in 1966.Comment: 21 pages, 0 figure
Stably free modules over virtually free groups
Let be the free group on generators and let be a finite
nilpotent group of non square-free order; we show that for each the
integral group ring has infinitely many stably free
modules of rank 1.Comment: 9 pages. The final publication is available at
http://www.springerlink.com doi:10.1007/s00013-012-0432-
Peak reduction technique in commutative algebra
The "peak reduction" method is a powerful combinatorial technique with
applications in many different areas of mathematics as well as theoretical
computer science. It was introduced by Whitehead, a famous topologist and group
theorist, who used it to solve an important algorithmic problem concerning
automorphisms of a free group. Since then, this method was used to solve
numerous problems in group theory, topology, combinatorics, and probably in
some other areas as well.
In this paper, we give a survey of what seems to be the first applications of
the peak reduction technique in commutative algebra and affine algebraic
geometry.Comment: survey; 10 page
Using clinical scenarios to understand preventability of Clostridium difficile infections by inpatient antibiotic stewardship programs
Land Use Implications of Expanding Biofuel Demand
The Renewable Fuel Standard mandates in the Energy Independence and Security Act of 2007 will require 36 billion gallons of ethanol to be produced in 2022. The mandates require that 16 of the 36 billion gallons must be produced from cellulosic feedstocks. The potential land use implications resulting from these mandates were examined using two methods, the POLYSYS model and a general equilibrium model. Results of the POLYSYS analysis indicated that 72.1 million tons of corn stover, 23.5 million tons of wheat straw, and 24.7 million acres would be used to produce 109 million tons of switchgrass in 2025 to meet the mandate. Results of the CGE analysis indicated that 10.9 billion bushels of corn grain, 71 million tons of corn stover, and 56,200 tons of switchgrass is needed to meet the mandate.cellulosic ethanol, corn stover, grain ethanol, renewable fuel standard, switchgrass, Crop Production/Industries, Demand and Price Analysis, Environmental Economics and Policy, Land Economics/Use, Resource /Energy Economics and Policy, Q15, Q42,
Validity of Critical Velocity Concept for Weighted Sprinting Performance
International Journal of Exercise Science 11(4): 900-909, 2018. We investigated the validity of a recently developed equation for predicting sprinting times of various tactical loads based upon the performance of a running 3-min all-out exercise test (3MT). Thirteen recreationally trained participants completed the running 3MT to determine critical velocity (CV) and finite running capacity for running velocities exceeding CV (D’). Two subsequent counterbalanced loaded sprints of 800 and 1000 m distances with 20 and 15% of their body mass, respectively, were evaluated. Estimated times (t, sec) for running 800 and 1000 m with a tactical load was derived using t = (D – D’)/CV. Critical velocity adjusted for an added load using the following regression equation: original CV + (-0.0638 x %load) + 0.6982, D was 800 or 1000 m, and whole percentage load was ~15 or 20% of the participant\u27s body mass. From the 3MT, CV (3.80 ±0.5 m.s-1) and D’(200 ±49.88 m) values were determined.The typical error of predicting actual times for the 800 and 1000 m loaded sprints were 5.6 and 10.1 s, with corresponding ICCs of 0.95 and 0.87, and coefficient of variations of 2.9 and 4.3%. The effect size differences between estimated and actual sprint times were small (0.27) and moderate (0.60) for 800 and 1000 m, respectively. The adjustment to CV through the regression equation yields small to moderate overestimates of maximally loaded sprint times for distances of 800 and 1000 m. Whether such errors remain pervasive for prescribing high-intensity interval training is unclear and requires further investigation
On Hyperbolic once-punctured-torus bundles II. Fractal tessellations of the plane
We describe fractal tessellations of the complex plane that arise naturally from Cannon-Thurston maps associated to complete, hyperbolic, once-punctured-torus bundles. We determine the symmetry groups of these tessellations
Monitoring interval-training responses for swimming using the 3-min all-out exercise test.
International Journal of Exercise Science 9(5): 545-553, 2016. The purpose of this study was to determine whether the 3-min all-out exercise test (3MT) could be applied to create an off-season high intensity, interval training (HIIT) program to improve performance, specifically critical velocity (CV), in the sport of swimming. We tested a group of competitive female swimmers (age = 19 ± 1 yrs, height = 169 ± 7 cm, body mass = 69 ± 9 kg) to determine their swimming CV and finite energy capacity \u3eCV (D’), and created a four week (2 d∙wk-1) personalized interval training program. Participants were divided in to two groups, a 150yd interval group (n =11) and a 250yd interval group (n =6). Each group completed a series of intervals designed to deplete a given percentage of D’ at velocities exceeding CV. A 3MT following the training period was administered to assess for any changes in CV, D’, average velocity during the first 150s of the test (V150s) and total distance traveled (D). Both groups improved their CV (+0.04 m∙s-1), V150s (+0.03 m∙s-1) and D (+8.64 m) (p \u3c 0.05), however, significant interactions for D’ between groups was not observed (p \u3e 0.05). We conclude that HIIT prescriptions based on a 3MT can improve swim performance over a four-week period. Future research on the fidelity of measuring CV and D’ using a swimming 3MT is needed to help aid practitioners in interpreting true training adaptations
Release of cell wall phenolic esters during hydrothermal pretreatment of rice husk and rice straw
Background: Rice husk and rice straw represent promising sources of biomass for production of renewable fuels and chemicals. For efficient utilisation, lignocellulosic components must first be pretreated to enable efficient enzymatic saccharification and subsequent fermentation. Existing pretreatments create breakdown products such as sugar-derived furans, and lignin-derived phenolics that inhibit enzymes and fermenting organisms. Alkali pretreatments have also been shown to release significant levels of simple, free phenolics such as ferulic acid that are normally esterified to cell wall polysaccharides in the intact plant. These phenolics have recently been found to have considerable inhibitory properties. The aim of this research has been to establish the extent to which such free phenolic acids are also released during hydrothermal pretreatment of rice straw (RS) and rice husk (RH). Results: RS and RH were subjected to hydrothermal pretreatments over a wide range of severities (1.57–5.45). FTIR analysis showed that the pretreatments hydrolysed and solubilised hemicellulosic moieties, leading to an enrichment of lignin and crystalline cellulose in the insoluble residue. The residues also lost the capacity for UV autofluorescence at pH 7 or pH 10, indicating the breakdown or release of cell wall phenolics. Saponification of raw RS and RH enabled identification and quantification of substantial levels of simple phenolics including ferulic acid (tFA), coumaric acid (pCA) and several diferulic acids (DiFAs) including 8-O-4′-DiFA, 8,5′-DiFA and 5,5′-DiFA. RH had higher levels of pCA and lower levels of tFA and DiFAs compared with RS. Assessment of the pretreatment liquors revealed that pretreatment-liberated phenolics present were not free but remained as phenolic esters (at mM concentrations) that could be readily freed by saponification. Many were lost, presumably through degradation, at the higher severities. Conclusion: Differences in lignin, tFA, DiFAs and pCA between RS and RH reflect differences in cell wall physiology, and probably contribute to the higher recalcitrance of RH compared with RS. Hydrothermal pretreatments, unlike alkali pretreatments, release cinnamic acid components as esters. The potential for pretreatment-liberated phenolic esters to be inhibitory to fermenting microorganisms is not known. However, the present study shows that they are found at concentrations that could be significantly inhibitory if released as free forms by enzyme activity
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