TOWARD A DEVELOPMENT POLICY FOR RURAL AMERICA: A COMMENT

Community/Rural/Urban Development,

THE ECONOMIC CONTRIBUTION OF AGRICULTURE IN DELAWARE: REPLY

Agribusiness,

THE CHANGING RURAL POLICY CONTEXT: DISCUSSION

This paper discusses a paper presented by Steven Smith at the 1995 annual meeting of the Northeastern Agricultural and Resource Economics Association. Smith presented key issues that have changed the context for rural development policy in the United States. We propose that the induced innovation model of economic development can be used to identify a variety of ways that LGU's can contribute to developing and delivering appropriate rural economic development programs. These ways include assisting rural communities in identifying comparative advantage, identifying and/or providing relevant resource persons, delivering appropriate educational programs and conducting research on important issues. The success of LGU's in these areas will depend on their willingness to undertake these activities and their ability to recognize and adapt to current to future economic and social realities affecting rural America.Community/Rural/Urban Development,

THE ECONOMIC CONTRIBUTION OF AGRICULTURE IN DELAWARE

The decreasing share of production agriculture in the U.S. economy in general and Delaware in particular has raised questions about the amount of government resources being spent on the local agricultural sector. A basic question in the debate is: "What is the real economic contribution of agriculture?" This study looks at the economic role of agriculture in Delaware, presenting different perspectives of what agriculture is and what it contributes to the state economy. Based on three definitions of agriculture, the economic impacts as measured by shares to total employment, output, and value added were estimated using IMPLAN, an input-output modeling software. In each economic impact measure, the share of the local agricultural sector to the total Delaware economy ranged from around 2% to 6% in 1991.Agribusiness,

Natural resource management - the creation of a new interdisciplinary major at the University of Delaware

The College of Agricultural Sciences at the University of Delaware has an excellent faculty and physical facility well positioned to educate students for managing the world\u27s natural resources (air, land, water, pants, animals, etc.) into the next century. The college offers a variety of traditional, discipline specific undergraduate majors in five academic departments. A faculty committee worked for more than two years to formulate a new major with an interdisciplinary approach. The result is a new major, Natural Resource Management, which began admitting freshman students in the Fall of 1997. This paper will discuss the creation of the Natural Resource Management major

Introducing problem-based learning techniques into the natural resources managment curriculum at the University of Delaware

Natural Resource Management is a relatively new interdisciplinary major in the College of Agriculture and Natural Resources at the University of Delaware. This paper describes the efforts of faculty to incorporate problem-based learning techniques into several courses in the Natural Resource Management major. It includes a brief history of the major; an overview of problem-based learning programs and initiatives at the University of Delaware; a discussion of problem-based learning techniques recently introduced into courses in statistics, community economic development, environmental law, and a senior capstone course; and observations by faculty and students on the problems and benefits of problem-based learning techniques

Disentangling trophic interactions inside a Caribbean marine reserve

Author Posting. © Ecological Society of America, 2010. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecological Applications 20 (2010): 1979–1992, doi:10.1890/09-1217.1.Recent empirical studies have demonstrated that human activities such as fishing can strongly affect the natural capital and services provided by tropical seascapes. However, policies to mitigate anthropogenic impacts can also alter food web structure and interactions, regardless of whether the regulations are aimed at single or multiple species, with possible unexpected consequences for the ecosystems and their associated services. Complex community response to management interventions have been highlighted in the Caribbean, where, contrary to predictions from linear food chain models, a reduction in fishing intensity through the establishment of a marine reserve has led to greater biomass of herbivorous fish inside the reserve, despite an increased abundance of large predatory piscivores. This positive multi-trophic response, where both predators and prey benefit from protection, highlights the need to take an integrated approach that considers how numerous factors control species coexistence in both fished and unfished systems. In order to understand these complex relationships, we developed a general model to examine the trade-offs between fishing pressure and trophic control on reef fish communities, including an exploration of top-down and bottom-up effects. We then validated the general model predictions by parameterizing the model for a reef system in the Bahamas in order to tease apart the wide range of species responses to reserves in the Caribbean. Combining the development of general theory and site-specific models parameterized with field data reveals the underlying driving forces in these communities and enables us to make better predictions about possible population and community responses to different management schemes.This work was supported by funding from the Bahamas Biocomplexity Project (U.S. NSF Biocomplexity grant OCE-0119976) and U.S. EPA Science to Achieve Results (R832223)

Isotopic characterization of nitrogen oxides (NOx), nitrous acid (HONO), and nitrate (pNO3−) from laboratory biomass burning during FIREX

New techniques have recently been developed and applied to capture reactive nitrogen species, including nitrogen oxides (NOx=NO+NO2), nitrous acid (HONO), nitric acid (HNO3), and particulate nitrate (pNO−3), for accurate measurement of their isotopic composition. Here, we report – for the first time – the isotopic composition of HONO from biomass burning (BB) emissions collected during the Fire Influence on Regional to Global Environments Experiment (FIREX, later evolved into FIREX-AQ) at the Missoula Fire Science Laboratory in the fall of 2016. We used our newly developed annular denuder system (ADS), which was verified to completely capture HONO associated with BB in comparison with four other high-time-resolution concentration measurement techniques, including mist chamber–ion chromatography (MC–IC), open-path Fourier transform infrared spectroscopy (OP-FTIR), cavity-enhanced spectroscopy (CES), and proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF). In 20 “stack” fires (direct emission within ∼5 s of production by the fire) that burned various biomass materials from the western US, δ15N–NOx ranges from −4.3 ‰ to +7.0 ‰, falling near the middle of the range reported in previous work. The first measurements of δ15N–HONO and δ18O–HONO in biomass burning smoke reveal a range of −5.3 ‰ to +5.8 ‰ and +5.2 ‰ to +15.2 ‰, respectively. Both HONO and NOx are sourced from N in the biomass fuel, and δ15N–HONO and δ15N–NOx are strongly correlated (R2=0.89, p\u3c0.001), suggesting HONO is directly formed via subsequent chain reactions of NOx emitted from biomass combustion. Only 5 of 20 pNO−3 samples had a sufficient amount for isotopic analysis and showed δ15N and δ18O of pNO−3 ranging from −10.6 ‰ to −7.4 ‰ and +11.5 ‰ to +14.8 ‰, respectively. Our δ15N of NOx, HONO, and pNO−3 ranges can serve as important biomass burning source signatures, useful for constraining emissions of these species in environmental applications. The δ18O of HONO and NO−3 obtained here verify that our method is capable of determining the oxygen isotopic composition in BB plumes. The δ18O values for both of these species reflect laboratory conditions (i.e., a lack of photochemistry) and would be expected to track with the influence of different oxidation pathways in real environments. The methods used in this study will be further applied in future field studies to quantitatively track reactive nitrogen cycling in fresh and aged western US wildfire plumes

Development stage-specific proteomic profiling uncovers small, lineage specific proteins most abundant in the Aspergillus Fumigatus conidial proteome

Background The pathogenic mold Aspergillus fumigatus is the most frequent infectious cause of death in severely immunocompromised individuals such as leukemia and bone marrow transplant patients. Germination of inhaled conidia (asexual spores) in the host is critical for the initiation of infection, but little is known about the underlying mechanisms of this process. Results To gain insights into early germination events and facilitate the identification of potential stage-specific biomarkers and vaccine candidates, we have used quantitative shotgun proteomics to elucidate patterns of protein abundance changes during early fungal development. Four different stages were examined: dormant conidia, isotropically expanding conidia, hyphae in which germ tube emergence has just begun, and pre-septation hyphae. To enrich for glycan-linked cell wall proteins we used an alkaline cell extraction method. Shotgun proteomic resulted in the identification of 375 unique gene products with high confidence, with no evidence for enrichment of cell wall-immobilized and secreted proteins. The most interesting discovery was the identification of 52 proteins enriched in dormant conidia including 28 proteins that have never been detected in the A. fumigatus conidial proteome such as signaling protein Pil1, chaperones BipA and calnexin, and transcription factor HapB. Additionally we found many small, Aspergillus specific proteins of unknown function including 17 hypothetical proteins. Thus, the most abundant protein, Grg1 (AFUA_5G14210), was also one of the smallest proteins detected in this study (M.W. 7,367). Among previously characterized proteins were melanin pigment and pseurotin A biosynthesis enzymes, histones H3 and H4.1, and other proteins involved in conidiation and response to oxidative or hypoxic stress. In contrast, expanding conidia, hyphae with early germ tubes, and pre-septation hyphae samples were enriched for proteins responsible for housekeeping functions, particularly translation, respiratory metabolism, amino acid and carbohydrate biosynthesis, and the tricarboxylic acid cycle. Conclusions The observed temporal expression patterns suggest that the A. fumigatus conidia are dominated by small, lineage-specific proteins. Some of them may play key roles in host-pathogen interactions, signal transduction during conidial germination, or survival in hostile environments

Non-intersecting squared Bessel paths at a hard-edge tacnode

The squared Bessel process is a 1-dimensional diffusion process related to the squared norm of a higher dimensional Brownian motion. We study a model of $n$ non-intersecting squared Bessel paths, with all paths starting at the same point $a>0$ at time $t=0$ and ending at the same point $b>0$ at time $t=1$. Our interest lies in the critical regime $ab=1/4$, for which the paths are tangent to the hard edge at the origin at a critical time $t^*\in (0,1)$. The critical behavior of the paths for $n\to\infty$ is studied in a scaling limit with time $t=t^*+O(n^{-1/3})$ and temperature $T=1+O(n^{-2/3})$. This leads to a critical correlation kernel that is defined via a new Riemann-Hilbert problem of size $4\times 4$. The Riemann-Hilbert problem gives rise to a new Lax pair representation for the Hastings-McLeod solution to the inhomogeneous Painlev\'e II equation $q"(x) = xq(x)+2q^3(x)-\nu,$ where $\nu=\alpha+1/2$ with $\alpha>-1$ the parameter of the squared Bessel process. These results extend our recent work with Kuijlaars and Zhang \cite{DKZ} for the homogeneous case $\nu = 0$.Comment: 54 pages, 13 figures. Corrected error in Theorem 2.