Multivariate AIM Consumer Demand Model Applied to Dried Fruit, Raisins, and Dried Plums

Abstract: We estimate a semi-nonparametric demand system based on a multivariate version of the Muntz-Szatz series expansion which is called the Asymptotically Ideal Model (AIM). The model is applied to consumer demand for dried fruits, raisins, and dried plums. Results from the first and second order AIM expansions suggest that the second order expansion leads to a more economically consistent model, but the likelihood ratio test indicates the AIM(2) model was not a statistical improvement over the AIM(1) model.demand, consumers, AIM, Demand and Price Analysis,

RESEARCH PRODUCTIVITY AND SELECTED CHARACTERISTICS OF AGRICULTURAL ECONOMICS FACULTY IN THE SOUTHERN REGION: A QUARTER OF A CENTURY LATER

Productivity and characteristics of southern agricultural economics faculty was compared to other regional faculty. With few exceptions, faculty members in the Southern region are as productive as their counterparts. We also found that the majority of respondents in all regions considered themselves in the top-quartile in all areas.Teaching/Communication/Extension/Profession,

Assessing Critical Thinking Skills through Collegiate Livestock Evaluation Participation

Career-building competitions, such as collegiate livestock evaluation, claim to enhance writing and speaking skills, confidence in making decisions, teamwork, and critical thinking skills of participants, yet there is limited data to validate these claims. The aim of this study was to assess and record the role participating on a collegiate livestock team might play in developing critical thinking skills. The Watson-Glaser™ II Critical Thinking Appraisal (WGCTA) exam provided a way to objectively assess and record the critical thinking skills of collegiate livestock evaluators at two community colleges and two universities. Demographic information was obtained from 84 study participants to describe the characteristics of collegiate livestock evaluation. Although no statistically significant correlations were found between the demographic components and WGCTA scores, university participants recorded higher WGCTA mean scores in comparison to community college evaluators (P = 0.0019). The primary objective of this study was to assess the critical thinking level of collegiate livestock evaluation team members. The mean WGCTA score for all evaluators was (M = 20.92, SD = 4.65) out of a possible 40. The overall mean of community college participants (M = 19.30, SD = 3.52) and university participants (M = 22.39, SD = 5.08) was tabulated. In this study, male participants recorded higher mean WGCTA scores (M = 21.13, SD = 4.90) than females’ (M = 20.56, SD = 4.25); although a difference of 0.57 was recorded, a t-test concluded there was no significant statistical difference between the total raw critical thinking scores across genders. Participants with a GPA between 3.0–3.49 recorded the highest mean score in this study (M = 21.47, SD = 4.99), followed by those with a GPA of 3.5 and greater (M = 20.85, SD = 4.39), while participants with a GPA less than 2.9 recorded the lowest WGCTA mean (M = 19.00, SD = 1.42). A Pearson product-moment correlation was computed and identified a positive correlation between Top 10 individual finishes and the number of Top 10 finishes in oral reasons (r^2 = 0.84, n = 84, p < .0001). A positive correlation was discovered between Top 10 oral reason finishes and the number of contests attended (r^2 = 0.66, n = 84, p < .0001). Additionally, a positive correlation existed between Top 10 individual finishes and the number of contests attended (r = 0.59, n = 84, p < .0001). Likewise, as the total number of contests attended increased, the number of Top 10 finishes in oral reasons and Top 10 finishes individually increased. The mean WGCTA score for all livestock evaluators in this study was (M = 20.92, SD = 4.65) out of a possible 40, which positions collegiate livestock evaluators in the 22nd percentile of the 3–4 years of college norm group. These results contrast the findings of previous work, where participants from collegiate evaluation teams recorded higher critical thinking skills than non-evaluators. The results of this study indicate the need to incorporate various training activities to stimulate the development of critical thinking skills of collegiate livestock evaluators

Black Holes in Galaxy Mergers: Evolution of Quasars

Based on numerical simulations of gas-rich galaxy mergers, we discuss a model in which quasar activity is tied to the self-regulated growth of supermassive black holes in galaxies. Nuclear inflow of gas attending a galaxy collision triggers a starburst and feeds black hole growth, but for most of the duration of the starburst, the black hole is heavily obscured by surrounding gas and dust which limits the visibility of the quasar, especially at optical and UV wavelengths. Eventually, feedback energy from accretion heats the gas and expels it in a powerful wind, leaving a 'dead quasar'. Between buried and dead phases there is a window during which the galaxy would be seen as a luminous quasar. Because the black hole mass, radiative output, and distribution of obscuring gas and dust all evolve strongly with time, the duration of this phase of observable quasar activity depends on both the waveband and imposed luminosity threshold. We determine the observed and intrinsic lifetimes as a function of luminosity and frequency, and calculate observable lifetimes ~10 Myr for bright quasars in the optical B-band, in good agreement with empirical estimates and much smaller than the black hole growth timescales ~100 Myr, naturally producing a substantial population of 'buried' quasars. However, observed and intrinsic energy outputs converge in the IR and hard X-ray bands as attenuation becomes weaker and chances of observation greatly increase. We obtain the distribution of column densities along sightlines in which the quasar is seen above a given luminosity, and find that our result agrees remarkably well with observed estimates of the column density distribution from the SDSS for appropriate luminosity thresholds. (Abridged)Comment: 12 pages, 7 figures. Accepted for publication in ApJ (September 2005). Replacement with minor revisions from referee repor

The Relation Between Quasar and Merging Galaxy Luminosity Functions and the Merger-Induced Star Formation Rate of the Universe

Using a model for self-regulated growth of black holes (BHs) in mergers involving gas-rich galaxies, we study the relationship between quasars and the population of merging galaxies and predict the merger-induced star formation rate density of the Universe. Mergers drive nuclear gas inflows, fueling starbursts and 'buried quasars' until accretion feedback expels the gas, rendering a briefly visible optical quasar. Star formation is shut down and accretion declines, leaving a passively evolving remnant with properties typical of red, elliptical galaxies. Based on evolution of these events in our simulations, we demonstrate that the observed statistics of merger rates, luminosity functions (LFs) and mass functions, SFR distributions, specific SFRs, quasar and quasar host galaxy LFs, and elliptical/red galaxy LFs are self-consistent and follow from one another as predicted by the merger hypothesis. We use our simulations to de-convolve both quasar and merging galaxy LFs to determine the birthrate of black holes of a given final mass and merger rates as a function of stellar mass. We use this to predict the merging galaxy LF in several observed wavebands, color-magnitude relations, mass functions, absolute and specific SFR distributions and SFR density, and quasar host galaxy LFs, as a function of redshift from z=0-6. We invert this and predict e.g. quasar LFs from observed merger LFs or SFR distributions. Our results agree well with observations, but idealized models of quasar lightcurves are ruled out by comparison of merger and quasar observations at >99.9% confidence. Using only observations of quasars, we estimate the contribution of mergers to the SFR density of the Universe even to high redshifts z~4.Comment: 26 pages, 15 figures, matches version accepted to Ap

Comparison of cardiovascular health profiles across population surveys from five high- to low-income countries

Aims With the greatest burden of cardiovascular disease morbidity and mortality increasingly observed in lower-income countries least prepared for this epidemic, focus is widening from risk factor management alone to primordial prevention to maintain high levels of cardiovascular health (CVH) across the life course. To facilitate this, the American Heart Association (AHA) developed CVH scoring guidelines to evaluate and track CVH. We aimed to compare the prevalence and trajectories of high CVH across the life course using nationally representative adult CVH data from five diverse high- to low-income countries. Methods Surveys with CVH variables (physical activity, cigarette smoking, body mass, blood pressure, blood glucose, and total cholesterol levels) were identified in Ethiopia, Bangladesh, Brazil, England, and the United States (US). Participants were included if they were 18-69y, not pregnant, and had data for these CVH metrics. Comparable data were harmonized and each of the CVH metrics was scored using AHA guidelines as high (2), moderate (1), or low (0) to create total CVH scores with higher scores representing better CVH. High CVH prevalence by age was compared creating country CVH trajectories. Results The analysis included 28,092 adults (Ethiopia n=7686, 55.2% male; Bangladesh n=6731, 48.4% male; Brazil n=7241, 47.9 % male; England n=2691, 49.5% male, and the US n=3743, 50.3% male). As country income level increased, prevalence of high CVH decreased (>90% in Ethiopia, >68% in Bangladesh and under 65% in the remaining countries). This pattern remained using either five or all six CVH metrics and following exclusion of underweight participants. While a decline in CVH with age was observed for all countries, higher income countries showed lower prevalence of high CVH already by age 18y. Excess body weight appeared the main driver of poor CVH in higher income countries, while current smoking was highest in Bangladesh. Conclusion Harmonization of nationally representative survey data on CVH trajectories with age in 5 highly diverse countries supports our hypothesis that CVH decline with age may be universal. Interventions to promote and preserve high CVH throughout the life course are needed in all populations, tailored to country-specific time courses of the decline. In countries where CVH remains relatively high, protection of whole societies from risk factor epidemics may still be feasible.This study was funded with support from the Institute for Global Health, Northwestern University [Catalyzer Award No. 1005]; from the DSI-NRF Centre of Excellence in Human Development hosted at the University of the Witwatersrand in South Africa, and the support of the University of the Witwatersrand research office

Evaluation of atmospheric dry deposition as a source of nutrients and trace metals to Lake Tahoe

Atmospheric deposition can be an important source of nutrients and trace metals to oligotrophic alpine lakes, affecting their biogeochemistry. We measured trace metal concentrations and lead (Pb) isotope ratios in lake water, river water, ground water, and aerosol total suspended particles (TSP), as well as nutrient (NO 3 − , NH 4 + , PO 4 3− ) concentrations in TSP in the Tahoe Basin. The contribution of TSP deposition to the lake trace metal budget was assessed. Our results show seasonality in TSP and associated trace metal concentrations with higher concentrations during Oct – April. However, trace metal solubilities are higher during May – Sept, resulting in a higher contribution of soluble trace metals to the lake water. The source of most of the trace metals in TSP in the Lake Tahoe Basin is mineral dust; however, Zn, Cu, and Cd also have an anthropogenic origin. Among major nutrients, NO 3 − concentrations are slightly higher during Oct – April, while NH 4 + and soluble reactive phosphorus (SRP) are higher during May – Sept. The distributions of trace metal concentrations and Pb isotopic ratios are homogenous throughout the lake water column, suggesting that the residence time of the trace metals in the lake is longer than the lake water mixing time. The contribution of atmospheric TSP deposition to the upper 20 m of lake water trace metal inventory is low, ranging from 0.03% for V to 5.7% for Mn. A triple-isotopes plot of Pb indicates that riverine and groundwater inputs are the major Pb sources, but aerosols still contribute some Pb to the lake. This article is part of a special issue entitled: Conway GEOTRACES - edited by Tim M. Conway, Tristan Horner, Yves Plancherel, and Aridane G. González

How can frontline expertise and new models of care best contribute to safely reducing avoidable acute admissions? A mixed-methods study of four acute hospitals

Background: Hospital emergency admissions have risen annually, exacerbating pressures on emergency departments (EDs) and acute medical units. These pressures have an adverse impact on patient experience and potentially lead to suboptimal clinical decision-making. In response, a variety of innovations have been developed, but whether or not these reduce inappropriate admissions or improve patient and clinician experience is largely unknown. Aims: To investigate the interplay of service factors influencing decision-making about emergency admissions, and to understand how the medical assessment process is experienced by patients, carers and practitioners. Methods: The project used a multiple case study design for a mixed-methods analysis of decision-making about admissions in four acute hospitals. The primary research comprised two parts: value stream mapping to measure time spent by practitioners on key activities in 108 patient pathways, including an embedded study of cost; and an ethnographic study incorporating data from 65 patients, 30 carers and 282 practitioners of different specialties and levels. Additional data were collected through a clinical panel, learning sets, stakeholder workshops, reading groups and review of site data and documentation. We used a realist synthesis approach to integrate findings from all sources. Findings: Patients’ experiences of emergency care were positive and they often did not raise concerns, whereas carers were more vocal. Staff’s focus on patient flow sometimes limited time for basic care, optimal communication and shared decision-making. Practitioners admitted or discharged few patients during the first hour, but decision-making increased rapidly towards the 4-hour target. Overall, patients’ journey times were similar, although waiting before being seen, for tests or after admission decisions, varied considerably. The meaning of what constituted an ‘admission’ varied across sites and sometimes within a site. Medical and social complexity, targets and ‘bed pressure’, patient safety and risk, each influenced admission/discharge decision-making. Each site responded to these pressures with different initiatives designed to expedite appropriate decision-making. New ways of using hospital ‘space’ were identified. Clinical decision units and observation wards allow potentially dischargeable patients with medical and/or social complexity to be ‘off the clock’, allowing time for tests, observation or safe discharge. New teams supported admission avoidance: an acute general practitioner service filtered patients prior to arrival; discharge teams linked with community services; specialist teams for the elderly facilitated outpatient treatment. Senior doctors had a range of roles: evaluating complex patients, advising and training juniors, and overseeing ED activity. Conclusions: This research shows how hospitals under pressure manage complexity, safety and risk in emergency care by developing ‘ground-up’ initiatives that facilitate timely, appropriate and safe decision-making, and alternative care pathways for lower-risk, ambulatory patients. New teams and ‘off the clock’ spaces contribute to safely reducing avoidable admissions; frontline expertise brings value not only by placing senior experienced practitioners at the front door of EDs, but also by using seniors in advisory roles. Although the principal limitation of this research is its observational design, so that causation cannot be inferred, its strength is hypothesis generation. Further research should test whether or not the service and care innovations identified here can improve patient experience of acute care and safely reduce avoidable admissions. Funding: The National Institute for Health Research (NIHR) Health Services and Delivery Research programme (project number 10/1010/06). This research was supported by the NIHR Collaboration for Leadership in Applied Health Research and Care South West Peninsula