SUPPLY AND DEMAND RISKS IN LABORATORY FORWARD AND SPOT MARKETS: IMPLICATIONS FOR AGRICULTURE

Laboratory experimental methods are used to investigate the impacts of supply and/or demand risks on prices, quantities traded, and earnings within forward and spot market institutions. Random demand and/or supply shifts can be as much as 25 percent of the expected equilibrium outcome. Nevertheless, results suggest that the spot or forward trading institution itself has a greater influence on market outcomes than the presence of risk within the trading institutions. Sellers tend to have relatively higher earnings in a spot market than buyers, regardless of the risk. Total surplus, however, generally is greater in a forward market.laboratory markets, forward market, spot market, supply and/or demand risks, Demand and Price Analysis, Marketing,

Insecticide ear tags numerically improve grazing cattle performance

Stocker cattle grazing pastures during the summer months face challenges due to horn flies, which can result in reduced weight gains and less efficient use of forages. One strategy for controlling horn flies is insecticide-impregnated ear tags. The use of pesticide ear tags may be an effective management practice to improve overall productivity during a grazing season. The objective of this study was to evaluate the efficacy of insecticide ear tags as a means of improving growth of stocker calves grazing native pastures in the Flint Hills region of Kansas

SUPPLY AND DEMAND RISKS IN FORWARD AND SPOT MARKETS: IMPLICATIONS FOR AGRICULTURE

Laboratory methods are used to investigate the impacts of supply and/or demand risks on prices, quantities traded, and earnings within forward and spot market institutions. Results suggest that the spot or forward trading institution itself has a greater influence on market outcomes than supply/demand risks within the institution.Marketing,

Cyclic Adenosine Monophosphate Accumulation and beta-Adrenergic Binding in Unweighted and Denervated Rat Soleus Muscle

Unweighting, but not denervation, of muscle reportedly "spares" insulin receptors, increasing insulin sensitivity. Unweighting also increases beta-adrenergic responses of carbohydrate metabolism. These differential characteristics were studied further by comparing cyclic adenosine monophosphate (cAMP) accumulation and beta-adrenergic binding in normal and 3-day unweighted or denervated soleus muscle. Submaximal amounts of isoproterenol, a p-agonist, increased cAMP accumulation in vitro and in vivo (by intramuscular (IM) injection) to a greater degree (P less than .05) in unweighted muscles. Forskolin or maximal isoproterenol had similar in vitro effects in all muscles, suggesting increased beta-adrenergic sensitivity following unweighting. Increased sensitivity was confirmed by a greater receptor density (B(sub max)) for iodo-125(-)-pindolol in particulate preparations of unweighted (420 x 10(exp -18) mol/mg muscle) than of control or denervated muscles (285 x 10(exp-18) mol/mg muscle). The three dissociation constant (Kd) values were similar (20.3 to 25.8 pmol/L). Total binding capacity (11.4 fmol/muscle) did not change during 3 days of unweighting, but diminished by 30% with denervation. This result illustrates the "sparing" and loss of receptors, respectively, in these two atrophy models. In diabetic animals, IM injection of insulin diminished CAMP accumulation in the presence of theophylline in unweighted muscle (-66% +/- 2%) more than in controls (-42% +'- 6%, P less than .001). These results show that insulin affects CAMP formation in muscle, and support a greater in vivo insulin response following unweighting atrophy. These various data support a role for lysosomal proteolysis in denervation, but not in unweighting, atrophy

North American Hard Yellow Liver Disease: An Old Problem Readdressed

Hard yellow liver disease or fatty cirrhosis periodically affects cattle, sheep, goats, pronghorn antelope (Antilocapra americana) and whitetail deer (Odocoileus virginianus texanus) within several Texas counties in the United States. Clinically it presents as chronic liver disease with progressive hepatic necrosis and fibrosis, icterus and liver failure. The damaged livers are yellow and many have multiple firm, often gritty foci that are scattered throughout all lobes. Early investigations included feeding studies using potential toxic plants, climate and forage studies, infectious disease surveys and various mycotoxin studies and analyses. None have definitively reproduced the disease or identified the inciting cause. However, the problem continues and recent outbreaks have allowed the collection of additional frozen tissues, and numerous paraffin tissue blocks and slides for additional studies. The objectives for this work are to evaluate and compare the microscopic changes, special histochemical studies, microbial and fungal surveys and chemical assays for dehyro-pyrrolizidine alkaloid (DHPA) metabolites of these additional cases with historical reports. These bovine livers had a spectrum of lesions including lipid degeneration and necrosis, eosinophilic granulomatous hepatitis, focal follicular lymphoid proliferation and chronic fibrosing hepatitis with dystrophic mineralization. No pyrrolizidine alkaloid metabolites were detected in any of the livers and select special stains did not reveal any fungal, bacterial or parasitic etiologies. The lack of findings and mixed histologic presentation suggest that this syndrome is a collection of chronic diseases probably of various etiologies. Earlier animal surveillance work is needed in endemic areas to better understand the etiology and pathogenesis of this syndrome

Molecular characterization of Geitleria appalachiana sp. nov. (Nostocales, Cyanobacteria) and formation of Geitleriaceae fam. nov.

Geitleria was described from a limestone cave in Israel, and subsequently reported from caves of France, Romania, Spain, Florida, Costa Rica, and Cook Islands. It is morphologically unusual in that it has true branching, but no heterocytes. A morphologically distinct species of Geitleria was recently collected from a limestone cave in Great Smoky Mountains National Park, Tennessee, and is herein described as G. appalachiana sp. nov. Sequence data for 16S rRNA and rpoC1 loci for the species were obtained from field material using single filament PCR. Phylogenetic evidence indicates that Geitleria does not belong to any family in the Nostocales containing true–branching genera, i.e. Hapalosiphonaceae, Chlorogloeopsidaceae, and Symphyonemataceae, and consequently Geitleriaceae fam. nov. is established to contain this unique genus

An Interactive Tutorial for Teaching Statistical Power

This paper describes an interactive Web-based tutorial that supplements instruction on statistical power. This freely available tutorial provides several interactive exercises that guide students as they draw multiple samples from various populations and compare results for populations with differing parameters (for example, small standard deviation versus large standard deviation). The tutorial assignment includes diagnostic multiple-choice questions with feedback addressing misconceptions, and follow-up questions suitable for grading. The sampling exercises utilize an interactive Java applet that graphically demonstrates relationships between statistical power and effect size, null and alternative populations and sampling distributions, and Type I and II error rates. The applet allows students to manipulate the mean and standard deviation of populations, sample sizes, and Type I error rate. Students (n = 84) enrolled in introductory and intermediate statistics courses overwhelmingly rated the tutorial as clear, useful, easy to use, and they reported increased comfort with the topic of statistical power after using the tutorial. Students who used the tutorial outperformed those who did not use the tutorial on a final exam question measuring knowledge of the factors influencing statistical power

Individual differences in self-affirmation: distinguishing self-affirmation from positive self-regard

Research into self-affirmation has almost exclusively employed experimental manipulations. In this paper we address individual differences in the tendency to respond to threats with self-affirming cognitions and distinguish this from two overlapping constructs: habitual positive self-thought and trait self-esteem. Items we designed to measure self-affirmation were represented by three first-order factors and loaded on a higher-order factor, creating the Spontaneous Self-Affirmation Measure (SSAM). The SSAM correlated moderately with self-esteem and habitual positive self-thought. In competitive analyses, the SSAM was an independent predictor of a large number of outcomes. The studies provide evidence about the correlates of individual differences in reported spontaneous self-affirmation in response to threat and the contribution made to this response by habitual positive self-thought and trait self-esteem

How Birds Combat Ectoparasites

Birds are plagued by an impressive diversity of ectoparasites, ranging from feather-feeding lice, to feather-degrading bacteria. Many of these ectoparasites have severe negative effects on host fitness. It is therefore not surprising that selection on birds has favored a variety of possible adaptations for dealing with ectoparasites. The functional significance of some of these defenses has been well documented. Others have barely been studied, much less tested rigorously. In this article we review the evidence--or lack thereof--for many of the purported mechanisms birds have for dealing with ectoparasites. We concentrate on features of the plumage and its components, as well as anti-parasite behaviors. In some cases, we present original data from our own recent work. We make recommendations for future studies that could improve our understanding of this poorly known aspect of avian biology