Neural Orchestration of the C. elegans Escape Response: A Dissertation

How does a nervous system orchestrate compound behaviors? Finding the neural basis of behavior requires knowing which neurons control the behavior and how they are connected. To accomplish this we measured and manipulated neural activity in a live, behaving animal with a completely defined connectome. The C. elegans escape response is a compound behavior consisting of a sequence of behavioral motifs. Gentle touch induces a reversal and suppression of head movements, followed by a deep turn allowing the animal to navigate away from the stimulus. The connectome provides a framework for the neural circuit that controls this behavior. We used optical physiology to determine the activity patterns of individual neurons during the behavior. Calcium imaging of locomotion interneurons and motor neurons reveal unique activity profiles during different motifs of the escape response. Furthermore, we used optogenetics and laser ablations to determine the contribution of individual neurons to each motif. We show these that the suppression of head movements and turning motifs are distinct motor programs and can be uncoupled from the reversal. The molecular mechanisms that regulate these motifs involve from signaling with the neurotransmitter tyramine. Tyramine signaling and gap junctions between locomotion interneurons and motor neurons regulate the temporal orchestration of the turning motif with the reversal. Additionally, tyramine signaling through a GPCR in GABAergic neurons facilitates the asymmetric turning during forward viii locomotion. The combination of optical tools and genetics allows us to dissect a how a neural circuit converts sensory information into a compound behavior

Arginase from kiwifruit: properties and seasonal variation

The in vitro activity of arginase (EC 3.5.3.1) was investigated in youngest-mature leaves and roots (1-3 mm diameter) of kiwifruit vines (Actinidia deliciosa var. deliciosa) during an annual growth cycle, and enzyme from root material partially purified. No seasonal trend in the specific activity of arginase was observed in roots. Measurements in leaves, however, rose gradually during early growth and plateaued c. 17 weeks after budbreak. Changes in arginase activity were not correlated with changes in the concentration of arginine (substrate) or glutamine (likely end-product of arginine catabolism) in either tissue during the growth cycle. Purification was by (NH4)2SO4 precipitation and DEAE-cellulose chromatography. The kinetic properties of the enzyme, purified 60-fold over that in crude extracts, indicated a pH optimum of 8.8, and a Km (L-arginine) of 7.85 mM. Partially-purified enzyme was deactivated by dialysis against EDTA, and reactivated in the presence of Mn²⁺, Co²⁺, and Ni²⁺

Likelihood of death within one year among a national cohort of hospital inpatients in Scotland

No abstract available

AJAE Appendix: Challenges to the Development of a Dedicated Energy Crop

The material contained herein is supplementary to the article named in the title and published in the American Journal of Agricultural Economics, Volume 89, Number 5, December 2007.Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies,

Spatial Analysis of Rural Economic Development Using a Locally Weighted Regression Model

This study uses locally weighted regression to identify county-level characteristics that serve as drivers of creative employment throughout the southern United States. We found that higher per capita income, greater infrastructure investments, and the rural nature of a county tended to promote creative employment density, while higher scores on a natural amenity index had the opposite effect. We were also able to identify and map clusters of rural counties where the marginal effects of these variables on creative employment density were greatest. These findings should help rural communities to promote creative employment growth as a means of furthering rural economic development.creative class, locally weighted regression, natural amenities, rural economic development, Community/Rural/Urban Development,

Attacks intended to seriously harm and co-occurring drug use among youth in the United States

BACKGROUND: While it is known that substance use and violence co-occur, less is understood in terms of how this relationship might vary based on the degree of youth involvement in violence. OBJECTIVES: This study sought to examine the prevalence and degree that substance use disorders (SUD) and related intrapersonal and contextual factors were associated with violent attacks. METHOD: Repeated cross-sectional data from a population-based study (National Survey on Drug Use and Health) of youth ages 12–17 (n = 216,852) in the United States between 2002 and 2013 were pooled to increase the analytic sample size. Survey multinomial regression was used to examine psychosocial and substance use differences between youth reporting episodic (1–2 times, n = 13,091; 5.84%) and repeated violent attacks (3+ times, n = 1,819; 0.83%) in contrast with youth reporting no attacks. Additional analyses examined the association of sociodemographic, intrapersonal, and contextual factors with SUD among youth reporting violent attacks. RESULTS: The prevalence of SUD among youth with no attacks was 6% compared to 22% among episodic and 36% among repeatedly violent youth. Violence-involved youth were substantially more likely to experience elevated sensation-seeking, easy drug access, and recent drug offers and less likely to benefit from religiosity and protective substance use beliefs. CONCLUSIONS/IMPORTANCE: Findings highlight the importance of distinguishing between the various gradations of violence among youth in understanding the relationship between substance use and violence, and shed light on the intrapersonal and contextual factors that can help identify violent youth at greatest risk for substance use problems