DETERMINANTS OF DEMAND FOR BEEF: THE IMPACT OF FAT TRIMMING

Beef products, lower fat, consumer demand, demand elasticities, Demand and Price Analysis,

Adolescent D-amphetamine treatment in a rodent model of attention deficit/hyperactivity disorder: impact on cocaine abuse vulnerability in adulthood

RATIONALE: Stimulant medications for attention-deficit/hyperactivity disorder (ADHD) in adolescents remain controversial with respect to later development of cocaine abuse. Past research demonstrated that adolescent methylphenidate treatment increased several aspects of cocaine self-administration during adulthood using the spontaneously hypertensive rat (SHR) model of ADHD. Presently, we determined effects of the alternate stimulant medication, d-amphetamine, on cocaine self-administration. OBJECTIVES: We tested the hypothesis that adolescent d-amphetamine would not increase cocaine self-administration in adult SHR, given that d-amphetamine has a different mechanism of action than methylphenidate. METHODS: A pharmacologically relevant dose of d-amphetamine (0.5 mg/kg) or vehicle was administered throughout adolescence to SHR and two control strains, Wistar-Kyoto (WKY) and Wistar (WIS). Three aspects of cocaine abuse vulnerability were assessed in adulthood after discontinuing adolescent treatments: acquisition rate and dose-related responding under fixed (FR) and progressive (PR) ratio schedules. RESULTS: Adult SHR acquired cocaine self-administration faster and self-administered more cocaine across multiple doses compared to WKY and WIS under FR and PR schedules, indicating that SHR is a reliable animal model of comorbid ADHD and cocaine abuse. Relative to vehicle, SHR and WIS with adolescent d-amphetamine treatment self-administered less cocaine upon reaching acquisition criteria, and WIS additionally acquired cocaine self-administration more slowly and had downward shifts in FR and PR cocaine dose-response curves. WKY with adolescent d-amphetamine treatment acquired cocaine self-administration more quickly relative to vehicle. CONCLUSIONS: In contrast to methylphenidate, adolescent d-amphetamine did not augment cocaine self-administration in SHR. Adolescent d-amphetamine treatment actually protected against cocaine abuse vulnerability in adult SHR and WIS.National Institutes of Health grant DA011716 and the Clara Mayo Memorial Fellowship at Boston University. (DA011716 - National Institutes of Health; Clara Mayo Memorial Fellowship at Boston University)https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5026317/Published versio

FACTORS INFLUENCING SOUTHERN DAIRY FARMERS' CHOICE OF MILK HANDLERS

Survey data of 2,538 dairy farmers located in 12 southern states were used to analyze the factors influencing farmers' choice of milk handlers. Results from a qualitative response model indicate that a combination of price and non-price factors contribute to dairy farmers' attitudes toward their milk handlers. Specifically, the decision to change milk handlers was significantly influenced by prices paid and deductions charged. However, non-price factors including field services, friendly personnel, and loyalty to a handler contributed to the longer term affiliation of dairy farmers with their milk handlers.Dairy farmers, Milk handlers, Market channels, Qualitative response, Marketing, Agribusiness,

Inversion of spinning sound fields

A method is presented for the reconstruction of rotating monopole source distributions using acoustic pressures measured on a sideline parallel to the source axis. The method requires no \textit{a priori} assumptions about the source other than that its strength at the frequency of interest vary sinusoidally in azimuth on the source disc so that the radiated acoustic field is composed of a single circumferential mode. When multiple azimuthal modes are present, the acoustic field can be decomposed into azimuthal modes and the method applied to each mode in sequence. The method proceeds in two stages, first finding an intermediate line source derived from the source distribution and then inverting this line source to find the radial variation of source strength. A far-field form of the radiation integrals is derived, showing that the far field pressure is a band-limited Fourier transform of the line source, establishing a limit on the quality of source reconstruction which can be achieved using far-field measurements. The method is applied to simulated data representing wind-tunnel testing of a ducted rotor system (tip Mach number~0.74) and to control of noise from an automotive cooling fan (tip Mach number~0.14), studies which have appeared in the literature of source identification.Comment: Revised version of paper submitted to JASA; five more figures; expanded content with more discussion of error behaviour and relation to Nearfield Acoustical Holograph

The Effects of Evolutionary Adaptations on Spreading Processes in Complex Networks

A common theme among the proposed models for network epidemics is the assumption that the propagating object, i.e., a virus or a piece of information, is transferred across the nodes without going through any modification or evolution. However, in real-life spreading processes, pathogens often evolve in response to changing environments and medical interventions and information is often modified by individuals before being forwarded. In this paper, we investigate the evolution of spreading processes on complex networks with the aim of i) revealing the role of evolution on the threshold, probability, and final size of epidemics; and ii) exploring the interplay between the structural properties of the network and the dynamics of evolution. In particular, we develop a mathematical theory that accurately predicts the epidemic threshold and the expected epidemic size as functions of the characteristics of the spreading process, the evolutionary dynamics of the pathogen, and the structure of the underlying contact network. In addition to the mathematical theory, we perform extensive simulations on random and real-world contact networks to verify our theory and reveal the significant shortcomings of the classical mathematical models that do not capture evolution. Our results reveal that the classical, single-type bond-percolation models may accurately predict the threshold and final size of epidemics, but their predictions on the probability of emergence are inaccurate on both random and real-world networks. This inaccuracy sheds the light on a fundamental disconnect between the classical bond-percolation models and real-life spreading processes that entail evolution. Finally, we consider the case when co-infection is possible and show that co-infection could lead the order of phase transition to change from second-order to first-order.Comment: Submitte