Rangeland Production Risk Management in Wyoming

Production Economics,

Rangeland Production Risk Management in Montana

Risk and Uncertainty,

Alfalfa : An Economic Alternative to Corn?

Production costs and returns of alfalfa for different levels of management and at different prices are compared to shelled corn and corn silage, the major crops grown on the Belle Fourche Irrigation District

Influence of MWCNT/surfactant dispersions on the mechanical properties of Portland cement pastes

This work studies the reinforcing effect of Multi Walled Carbon Nanotubes (MWCNT) on cement pastes. A 0.35% solid concentration of MWCNT in powder was dispersed in deionized water with sodium dodecyl sulfate (cationic surfactant), cetylpyridinium chloride (anionic surfactant) and triton X-100 (amphoteric surfactant) using an ultrasonic tip processor. Three concentrations of each surfactant (1mM, 10mM and 100mM) were tested, and all samples were sonicated until an adequate dispersion degree was obtained. Cement pastes with additions of carbon nanotubes of 0.15% by mass of cement were produced in two steps; first the dispersions of MWCNT were combined with the mixing water using an ultrasonic tip processor to guarantee homogeneity, and then cement was added and mixed until a homogeneous paste was obtained. Direct tensile strength, apparent density and open porosity of the pastes were measured after 7 days of curing. It was found that the MWCNT/surfactants dispersions decrease the mechanical properties of the cement based matrix due to an increased porosity caused by the presence of surfactants. © Published under licence by IOP Publishing Ltd

Mechanisms of Addition and Substitution Reactions of Furfural and Derivatives

In a complete series of substitution reactions (such as halogenation, nitration, mercuration, etc.,) of furfural and its derivatives, it appears that substitution is preceded by addition. For example, in bromination, two atoms of bromine first add to give a relatively unstable intermediate which then loses hydrogen bromide. These preliminary additions may be 1, 2- or 1, 4- or 1, 6- additions depending upon reactants and upon experimental conditions. Accompanying some of these transformations are ring fission and ring closure, and rearrangements involving unsaturated linkages. Typical illustrations of these changes were presented

The Gumbel hypothesis test for left censored observations using regional earthquake records as an example

Annual maximum (AM) time series are incomplete (i.e., censored) when no events are included above the assumed censoring threshold (i.e., magnitude of completeness). We introduce a distrtibutional hypothesis test for left-censored Gumbel observations based on the probability plot correlation coefficient (PPCC). Critical values of the PPCC hypothesis test statistic are computed from Monte-Carlo simulations and are a function of sample size, censoring level, and significance level. When applied to a global catalog of earthquake observations, the left-censored Gumbel PPCC tests are unable to reject the Gumbel hypothesis for 45 of 46 seismic regions. We apply four different field significance tests for combining individual tests into a collective hypothesis test. None of the field significance tests are able to reject the global hypothesis that AM earthquake magnitudes arise from a Gumbel distribution. Because the field significance levels are not conclusive, we also compute the likelihood that these field significance tests are unable to reject the Gumbel model when the samples arise from a more complex distributional alternative. A power study documents that the censored Gumbel PPCC test is unable to reject some important and viable Generalized Extreme Value (GEV) alternatives. Thus, we cannot rule out the possibility that the global AM earthquake time series could arise from a GEV distribution with a finite upper bound, also known as a reverse Weibull distribution. Our power study also indicates that the binomial and uniform field significance tests are substantially more powerful than the more commonly used Bonferonni and false discovery rate multiple comparison procedures

Tradeoffs May Counteract Effects of Telecommunication Towers on Osprey Nesting

The number of telecommunication towers (TCTs) throughout the United States has and continues to increase exponentially. Increased TCT placement has been implicated in local population increases in platform nesting birds such as ospreys (Pandion haliaetus). However, osprey use of artificial structures can cause conflicts with humans because of economic costs and risks to human safety. Managers require better information regarding the effect of artificial nesting surfaces, such as TCTS, on osprey reproduction to make informed decisions regarding species conservation and to mitigate potential conflicts. The objective of our study was to evaluate the influence of TCTs on osprey productivity and adult nesting behaviors. From March to July 2019, we monitored 30 osprey nests located in western Kentucky, USA, on TCTs (n = 11), navigation channel markers (NCMs; n = 10), and natural surfaces (NATs; n = 9). We found no differences in nest success, productivity, or the proportion of male ospreys perched at the nest between surface types. Nests on NCMs received 1.9–2.1 times more fish than nests on NATs and TCTs, respectively. Moreover, NCMs experienced 5.4–8.0 times more disturbances per hour compared to NATs and TCTs, respectively. Our data suggest ospreys nesting on TCTs are productive contributors to local populations. We recommend deterrence of osprey nesting should be focused on locations that are unsafe for ospreys and/or pose insurmountable problems for communication infrastructure

Bivariate stochastic modeling of functional response with natural mortality

A correction due to Abbott (1925) is the standard method of dealing with control mortality in insect bioassay to estimate the mortality of an insect conditional on control mortality not having occurred. In this article a bivariate stochastic process for overall mortality is developed in which natural mortality and predation are jointly modeled to take account of the competing-risks associated with prey loss. The total mortality estimate from this model is essentially identical with that from more classical modeling. However, when predation loss is estimated in the absence of control mortality the results are somewhat different, with the estimate from the bivariate model being lower than that from using Abbott’s formula in conjunction with the classical model. It is argued that overdispersion in observed mortality data corresponds to correlated outcomes (death or survival) for the prey initially present, while Abbott’s correction relies implicitly on independence