DIVERSITY OF SOURCES FOR FRESH PRODUCE: IMPLICATIONS FOR LOCAL MARKETS

Number of suppliers, approximation of equal-shares market condition and market share held by in-state sources were calculated to determine diversity of sources for 10 fresh fruits and vegetables in eight U.S. wholesale markets. Specificity of growing conditions is associated with few supply sources, unequal market shares and limited purchases from in-state suppliers. For crops with few sources, lower perishability and greater transportability are correlated with greater balance in market shares. For crops with many supply sources, greater perishability and greater transportability are consistent with large market share from imports. Diversity across all commodities can increase market share for local producers.Concentration index, Fruits and vegetables, Source diversity, Marketing,

Examining the Home Interventionist Model of Care in Pediatric Asthma

Pediatric asthma disproportionately affects children living in urban areas and within families reporting an income below the poverty threshold. Home interventionist models of care, utilizing interventionists from the communities they serve, have been found to improve pediatric asthma symptoms and reduce Medicaid costs. Home interventionists, such as community health workers (CHWs) and Healthy Homes assessors (HHAs), focus on connecting care among schools, providers, and homes, and empowering families in accessing resources to overcome barriers to care. However, research is just beginning to understand how home interventionists create positive change among families within low-income, urban communities. This dissertation study used a qualitative data approach outlined in the author’s NHLBI-funded F31 training grant (PI: Dempster, F31HL158196) and secondary data analysis of an NHLBI-funded Asthma Empowerment grant that tested a randomized clinical trial of the community-based asthma program, RVA Breathes (PI: Everhart, U01HL138682). Participants in RVA Breathes identified predominantly African American or Black, resided in public housing, and reported an income below $25,000 a year in Richmond, VA. This mixed-methods dissertation examined the processes by which interventionists in RVA Breathes assisted families in managing their children’s asthma control over an 18-month period. Session notes and internal records from the RVA Breathes intervention were qualitatively analyzed in conjunction with caregiver and interventionist focus groups. Secondary data analyses used multilevel modeling to assess associations among caregiver stress, depressive symptoms, stressful life events, barriers to care, and asthma control over 18-months controlling for group assignment. Findings highlighted the positive impacts of RVA Breathes on families of children with asthma, even in the face of COVID-19. Caregivers and interventionists also provided recommendations for future intervention efforts. Quantitative analyses found improvements in caregiver stress, depressive symptoms, stressful life events, barriers to care, and asthma control over time. Using multilevel modelling, improvements in caregiver stress and stressful life events were associated with improvements in asthma control over time regardless of group assignment. Findings highlight the benefits of the RVA Breathes program for families of children with asthma and provide evidence for future models of care incorporating home interventionists

One, two, or three stars? An investigation of an unusual eclipsing binary candidate undergoing dramatic period changes

We report our investigation of 1SWASP J234401.81-212229.1, a variable with a 18 461.6 s period. After identification in a 2011 search of the SuperWASP archive for main-sequence eclipsing binary candidates near the distribution's short-period limit of ~0.20 d, it was measured to be undergoing rapid period decrease in our earlier work, though later observations supported a cyclic variation in period length. Spectroscopic data obtained in 2012 with the Southern African Large Telescope did not, however, support the interpretation of the object as a normal eclipsing binary. Here, we consider three possible explanations consistent with the data: a single-star oblique rotator model in which variability results from stable cool spots on opposite magnetic poles; a two-star model in which the secondary is a brown dwarf; and a three-star model involving a low-mass eclipsing binary in a hierarchical triple system. We conclude that the latter is the most likely model

EMERGENCE OF U.S. ORGANIC AGRICULTURE: CAN WE COMPETE?

This compilation of papers for principal papers session PP-03 at the AAEA 1998 Annual Meeting assesses the current status of the organic agriculture industry in the United States. Paper topics address production, market and certification issues faced by the industry, research challenges and emerging conditions shaping domestic and international markets.production, marketing, industry structure, international trade, certification, organic agriculture, Industrial Organization, International Relations/Trade, Marketing, Production Economics,

Graduate Students of Color: A Storied Path to the Professoriate

This article shares the knowledge we gained from the stories of graduate students of color as they discussed their career choices. It provides an emerging understanding of how a graduate student’s background and cultural values influence his or her decision to pursue a faculty career

An updated stellar census of the Quintuplet cluster

Context. Found within the central molecular zone, the Quintuplet is one of the most massive young clusters in the Galaxy. As a consequence it offers the prospect of constraining stellar formation and evolution in extreme environments. However, current observations suggest that it comprises a remarkably diverse stellar population that is difficult to reconcile with an instantaneous formation event. Aims. To better understand the nature of the cluster our aim is to improve observational constraints on the constituent stars. Methods. In order to accomplish this goal we present Hubble Space Telescope/NICMOS+WFC3 photometry and Very Large Telescope/SINFONI+KMOS spectroscopy for ∼100 and 71 cluster members, respectively. Results. Spectroscopy of the cluster members reveals the Quintuplet to be far more homogeneous than previously expected. All supergiants are classified as either O7–8 Ia or O9–B0 Ia, with only one object of earlier (O5 I–III) spectral type. These stars form a smooth morphological sequence with a cohort of seven early-B hypergiants and six luminous blue variables and WN9-11h stars, which comprise the richest population of such stars of any stellar aggregate known. In parallel, we identify a smaller population of late-O hypergiants and spectroscopically similar WN8–9ha stars. No further H-free Wolf–Rayet (WR) stars are identified, leaving an unexpectedly extreme ratio of 13:1 for WC/WN stars. A subset of the O9–B0 supergiants are unexpectedly faint, suggesting they are both less massive and older than the greater cluster population. Finally, no main sequence objects were identifiable. Conclusions. Due to uncertainties over which extinction law to apply, it was not possible to quantitatively determine a cluster age via isochrone fitting. Nevertheless, we find an impressive coincidence between the properties of cluster members preceding the H-free WR phase and the evolutionary predictions for a single, non-rotating 60 M⊙ star; in turn this implies an age of ∼3.0–3.6 Myr for the Quintuplet. Neither the late O-hypergiants nor the low luminosity supergiants are predicted by such a path; we suggest that the former either result from rapid rotators or are the products of binary driven mass-stripping, while the latter may be interlopers. The H-free WRs must evolve from stars with an initial mass in excess of 60 M⊙ but it appears difficult to reconcile their observational properties with theoretical expectations. This is important since one would expect the most massive stars within the Quintuplet to be undergoing core-collapse/SNe at this time; since the WRs represent an evolutionary phase directly preceding this event,their physical properties are crucial to understanding both this process and the nature of the resultant relativistic remnant. As such, the Quintuplet provides unique observational constraints on the evolution and death of the most massive stars forming in the local, high metallicity Universe

When and How Can Death Be an Adaptation?

The concept of phenoptosis (or programmed organismal death) is problematic with respect to most species (including humans) since it implies that dying of old age is an adaptation, which contradicts the established evolutionary theory. But can dying ever be a strategy to promote fitness? Given recent developments in our understanding of the evolution of altruism, particularly kin and multilevel selection theories, it is timely to revisit the possible existence of adaptive death. Here, we discuss how programmed death could be an adaptive trait under certain conditions found in organisms capable of clonal colonial existence, such as the budding yeast Saccharomyces cerevisiae and, perhaps, the nematode Caenorhabditis elegans. The concept of phenoptosis is only tenable if consistent with the evolutionary theory; this accepted, phenoptosis may only occur under special conditions that do not apply to most animal groups (including mammals)

Effects of Particle Shape on Growth Dynamics at Edges of Evaporating Colloidal Drops

We study the influence of particle shape on growth processes at the edges of evaporating drops. Aqueous suspensions of colloidal particles evaporate on glass slides, and convective flows during evaporation carry particles from drop center to drop edge, where they accumulate. The resulting particle deposits grow inhomogeneously from the edge in two-dimensions, and the deposition front, or growth line, varies spatio-temporally. Measurements of the fluctuations of the deposition front during evaporation enable us to identify distinct growth processes that depend strongly on particle shape. Sphere deposition exhibits a classic Poisson like growth process; deposition of slightly anisotropic particles, however, belongs to the Kardar-Parisi-Zhang (KPZ) universality class, and deposition of highly anisotropic ellipsoids appears to belong to a third universality class, characterized by KPZ fluctuations in the presence of quenched disorder