MARKET SEGMENTATION PRACTICES OF RETAIL CROP INPUT FIRMS

While market segmentation and the associated idea of target marketing are not new, there are questions about how the strategy of market segmentation and target marketing is being used in retail agribusiness firms. Previous research has demonstrated that distinct groups of farmers/customers exist (Alexander). However, retail crop input firms tend to be of modest size and are geographically bound. Both lack of resources and confinement to a specific geographic market present challenges for successful implementation of a market segmentation/target marketing strategy (Stolp). In this study, market segmentation/target marketing practices were explored in two types of crop input retailers: independently owned and operated firms (9 firms) and agricultural cooperatives (11 firms). A number of questions related to market segmentation/target marketing strategy were assessed via a web-based survey and telephone interviews. Referencing Best's seven-step framework, market segmentation is compared and contrasted by firm type; gaps in market segmentation strategy execution are identified; and challenges to implementing a market segmentation strategy are considered. Results show that market segmentation/target marketing was employed by 85% of the crop input retailers in the sample. Key gaps identified in market segmentation strategy execution include measuring market segment attractiveness; evaluating market segment profitability; developing a product-price positioning strategy for a tailored offering; expanding the positioning strategy to include promotional and sales elements of the marketing-mix; and evaluating the progress/success with each target market segment. Addressing these key gaps will aid industry professionals as they work to serve the needs of a continuously evolving farmer/customer base.market segmentation, target marketing, crop inputs, distribution channel, retailer

Market Segmentation Practices of Retail Crop Input Firms

The farmers targeted by crop input retailers may be divided into distinct groups or segments, but retail crop input firms vary in their ability to implement strategies to serve individual segments. In this study, segmentation practices among cooperatives and independently owned crop input retailers were explored. Addressing gaps between Best’s seven-step market segmentation framework and retailer practices will help practitioners serve evolving farmer-customers.market segmentation, target marketing, crop inputs, distribution channel, retailer, Marketing, Q10, Q13,

Development of a Tubular Biological Tissue-Engineered Heart Valve with Growth Potential

University of Minnesota Ph.D. dissertation. May 2016. Major: Biomedical Engineering. Advisor: Robert Tranquillo. 1 computer file (PDF); xi, 158 pages.This thesis investigates tissue-engineered cardiovascular devices for pediatric patients and their function and growth potential in preclinical testing. Specifically, engineered tissue tubes were fabricated by entrapping dermal fibroblasts in a fibrin gel and allowing them to replace it with circumferentially-aligned extracellular matrix. Following in vitro culture, the engineered tubes possessed physiological strength and were decellularized to increase their shelf-life and reduce their immunogenicity. An allogeneic tubular heart valve was fabricated by inserting one engineered tube inside of another and attaching them together using degradable sutures. Extensive hemodynamic testing was performed in order to optimize and verify valve design. The growth potential and in vivo function of a single engineered tube (as a pulmonary artery replacement) and pulmonary heart valve were evaluated in a growing lamb model. We observed extensive host cell invasion and growth of the valve root/single tube, but to a lesser degree in the leaflets, which resulted in diminished valve function. A modified animal model is proposed and proof-of-concept studies were performed in order to address this shortcoming

Motivating Factors for Philanthropy at a Ministry Preparation Graduate Institution

A qualitative case study was conducted to determine whether major donors to an institution of higher education that existed to prepare ministers and missionaries were perceived by the institution's leaders as motivated by organizational effectiveness, financial efficiency, or evaluations by donor watchdog agencies. The case study was conducted with the Graduate Institute of Applied Linguistics. The interview process was utilized to gain information individually from the president, a development consultant, an academic dean, and a former development director. Each participant was asked a series of 19 questions during the interview process. The results indicated that the leaders perceived that organizational effectiveness was a philanthropic motivator for major donors and measured it by the accomplishments of those who were trained at the institution. The results also indicated that the ministry preparation institution's leaders perceived financial efficiency to provide philanthropic motivation to major donors, though to a lesser degree than organizational effectiveness, and measured it by stewardship of funds. The results further indicated that the ministry preparation institution's leaders perceived that donor watchdog agency evaluations, specifically those of the Evangelical Council for Financial Accountability and Guidestar, provided philanthropic motivation for major donors. Additional research recommendations included studying how to report about organizational effectiveness in a manner meeting the needs of major donors and what motivates major donors of other education and nonprofit organizations, organizational effectiveness and/or financial efficiency

Fermi Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe

The Extragalactic Background Light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ~10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the gamma-ray flux of extragalactic sources such as blazars and Gamma-Ray Bursts (GRBs). The Large Area Telescope onboard Fermi detects a sample of gamma-ray blazars with redshift up to z~3, and GRBs with redshift up to z~4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of gamma-ray flux attenuation by the EBL. We place upper limits on the gamma-ray opacity of the Universe at various energies and redshifts, and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the "baseline" model of Stecker et al. (2006) can be ruled out with high confidence.Comment: 42 pages, 12 figures, accepted version (24 Aug.2010) for publication in ApJ; Contact authors: A. Bouvier, A. Chen, S. Raino, S. Razzaque, A. Reimer, L.C. Reye

A population of gamma-ray emitting globular clusters seen with the Fermi Large Area Telescope

Globular clusters with their large populations of millisecond pulsars (MSPs) are believed to be potential emitters of high-energy gamma-ray emission. Our goal is to constrain the millisecond pulsar populations in globular clusters from analysis of gamma-ray observations. We use 546 days of continuous sky-survey observations obtained with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope to study the gamma-ray emission towards 13 globular clusters. Steady point-like high-energy gamma-ray emission has been significantly detected towards 8 globular clusters. Five of them (47 Tucanae, Omega Cen, NGC 6388, Terzan 5, and M 28) show hard spectral power indices $(0.7 < \Gamma <1.4)$ and clear evidence for an exponential cut-off in the range 1.0-2.6 GeV, which is the characteristic signature of magnetospheric emission from MSPs. Three of them (M 62, NGC 6440 and NGC 6652) also show hard spectral indices $(1.0 < \Gamma < 1.7)$, however the presence of an exponential cut-off can not be unambiguously established. Three of them (Omega Cen, NGC 6388, NGC 6652) have no known radio or X-ray MSPs yet still exhibit MSP spectral properties. From the observed gamma-ray luminosities, we estimate the total number of MSPs that is expected to be present in these globular clusters. We show that our estimates of the MSP population correlate with the stellar encounter rate and we estimate 2600-4700 MSPs in Galactic globular clusters, commensurate with previous estimates. The observation of high-energy gamma-ray emission from a globular cluster thus provides a reliable independent method to assess their millisecond pulsar populations that can be used to make constraints on the original neutron star X-ray binary population, essential for understanding the importance of binary systems in slowing the inevitable core collapse of globular clusters.Comment: Accepted for publication in A&A. Corresponding authors: J. Kn\"odlseder, N. Webb, B. Pancraz

Assessing the uncertainties of model estimates of primary productivity in the tropical Pacific Ocean

Author Posting. © Elsevier B.V., 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Journal of Marine Systems 76 (2009): 113-133, doi:10.1016/j.jmarsys.2008.05.010.Depth-integrated primary productivity (PP) estimates obtained from satellite ocean color based models (SatPPMs) and those generated from biogeochemical ocean general circulation models (BOGCMs) represent a key resource for biogeochemical and ecological studies at global as well as regional scales. Calibration and validation of these PP models are not straightforward, however, and comparative studies show large differences between model estimates. The goal of this paper is to compare PP estimates obtained from 30 different models (21 SatPPMs and 9 BOGCMs) to a tropical Pacific PP database consisting of ~1000 14C measurements spanning more than a decade (1983- 1996). Primary findings include: skill varied significantly between models, but performance was not a function of model complexity or type (i.e. SatPPM vs. BOGCM); nearly all models underestimated the observed variance of PP, specifically yielding too few low PP (< 0.2 gC m-2d-2) values; more than half of the total root-mean-squared model-data differences associated with the satellite-based PP models might be accounted for by uncertainties in the input variables and/or the PP data; and the tropical Pacific database captures a broad scale shift from low biomass-normalized productivity in the 1980s to higher biomass-normalized productivity in the 1990s, which was not successfully captured by any of the models. This latter result suggests that interdecadal and global changes will be a significant challenge for both SatPPMs and BOGCMs. Finally, average root-mean-squared differences between in situ PP data on the equator at 140°W and PP estimates from the satellite-based productivity models were 58% lower than analogous values computed in a previous PP model comparison six years ago. The success of these types of comparison exercises is illustrated by the continual modification and improvement of the participating models and the resulting increase in model skill.This research was supported by a grant from the National Aeronautics and Space Agency Ocean Biology and Biogeochemistry program (NNG06GA03G), as well as by numerous other grants to the various participating investigator

Homeostatic mechanisms in dopamine synthesis and release: a mathematical model

<p>Abstract</p> <p>Background</p> <p>Dopamine is a catecholamine that is used as a neurotransmitter both in the periphery and in the central nervous system. Dysfunction in various dopaminergic systems is known to be associated with various disorders, including schizophrenia, Parkinson's disease, and Tourette's syndrome. Furthermore, microdialysis studies have shown that addictive drugs increase extracellular dopamine and brain imaging has shown a correlation between euphoria and psycho-stimulant-induced increases in extracellular dopamine <abbrgrp><abbr bid="B1">1</abbr></abbrgrp>. These consequences of dopamine dysfunction indicate the importance of maintaining dopamine functionality through homeostatic mechanisms that have been attributed to the delicate balance between synthesis, storage, release, metabolism, and reuptake.</p> <p>Methods</p> <p>We construct a mathematical model of dopamine synthesis, release, and reuptake and use it to study homeostasis in single dopaminergic neuron terminals. We investigate the substrate inhibition of tyrosine hydroxylase by tyrosine, the consequences of the rapid uptake of extracellular dopamine by the dopamine transporters, and the effects of the autoreceoptors on dopaminergic function. The main focus is to understand the regulation and control of synthesis and release and to explicate and interpret experimental findings.</p> <p>Results</p> <p>We show that the substrate inhibition of tyrosine hydroxylase by tyrosine stabilizes cytosolic and vesicular dopamine against changes in tyrosine availability due to meals. We find that the autoreceptors dampen the fluctuations in extracellular dopamine caused by changes in tyrosine hydroxylase expression and changes in the rate of firing. We show that short bursts of action potentials create significant dopamine signals against the background of tonic firing. We explain the observed time courses of extracellular dopamine responses to stimulation in wild type mice and mice that have genetically altered dopamine transporter densities and the observed half-lives of extracellular dopamine under various treatment protocols.</p> <p>Conclusion</p> <p>Dopaminergic systems must respond robustly to important biological signals such as bursts, while at the same time maintaining homeostasis in the face of normal biological fluctuations in inputs, expression levels, and firing rates. This is accomplished through the cooperative effect of many different homeostatic mechanisms including special properties of tyrosine hydroxylase, the dopamine transporters, and the dopamine autoreceptors.</p