1,144 research outputs found
Pin cherry effects on Allegheny hardwood stand development
No full text Pin cherry (Prunus pensylvanica L.) develops an early height advantage over associated species. Data from three long-term studies, extending up to 70 years after complete overstory removal, were used to evaluate the effects of pin cherry density on associates. Survival of seedling-origin stems of black cherry (Prunus serotina Ehrh.), red maple (Acer rubrum L.), and sugar maple (Acer saccharum Marsh.) at age 15 decreased as the density of pin cherry >1.5 m tall at age 3 increased. The regression of pin cherry with black cherry was particularly strong (R2 = 0.632). Height of the tallest black cherry and white ash (Fraxinus americana L.) at age 15 also decreased. If the density of pin cherry at age 3 was > 1 stem > 1.5 m tall per 0.0004 ha (high density), the number of black cherry fell below full stocking at age 15. When pin cherry occurred in high density, it lived longer than when it occurred at low density (< 1 stem > 1.5 m tall per 0.0004 ha). High pin cherry density early in stand development delayed the time when shade-intolerant and shade-intermediate species reached a stable proportion of the total basal area. In the long term, pin cherry reduced stand diameter and volume growth, particularly of black cherry. </jats:p
Examining the Role of Fairness in High Stakes Allocation Decisions
Full text linkRecent experimental evidence has led to a debate about the nature of utility functions in which people are concerned about the amount others earn, and what factors heighten or diminish social preference. We explore fairness by examining behavior across three variants of the dictator game. Using data from nearly 200 dictators allocating as much as $100 each, we observe that fairness considerations are very powerful—when subjects could reasonably believe that disproportionately low offers are “fair”, only 8-12 percent of dictators make positive offers. Examining the comparative static results from these allocation decisions, we find that recent theoretical models of inequality do a respectable job of explaining the data patterns.
A technical manual for stream improvement on Prince Edward Island
No full textby Todd Dupuis, Daryl Guignion, Rosie MacFarlane, and Robert Redmond ; prepared for Morell River Management Cooperative Inc.; Bibliography p. 141-142.Source type: Electronic(1
Bertha Boykin Todd & Rosalind Moore Mosley
No full textBertha Boykin Todd (r) and Rosalind Moore Mosley (l) at the dedication of the Bottle Chapel at Airlie Gardens.
Bertha Boykin Todd (1929- ) is a native of Sampson County, NC as well as an author, educator and civil rights leader. She was the librarian in 1952 at then all-black Williston High School, and helped to integrate the Wilmington YMCA. She was co-chairman for the Foundation observing the 1898 Riot Centennial. She has served on a variety of local, state, and national boards dealing with education and the promotion of equal rights during desegregation, and has recieved many awards for her efforts.
Rosalind Moore Mosley (1941-2012) was born in Wilmington, NC and is a member of Chestnut Street Presbyterian Church
The Endogenous Formation of Coalitions to Provide Public Goods: Theory and Experimental Evidence
Full text linkThis paper examines the endogenous formation of coalitions that provide public goods in which players implement a minimum participation requirement before deciding whether to join. We demonstrate theoretically that payoff-maximizing players will vote to implement efficient participation requirements and these coalitions will form. However, we also demonstrate that if some players are averse to inequality they can cause inefficient outcomes. Inequality-averse players can limit free riding by implementing larger than efficient coalitions or by blocking efficient coalitions from forming. We test the theory with experimental methods and observe individual behavior and coalition formation consistent with a model of inequality-averse players.public goods, coalition formation, inequality aversion, participation requirement, experiments
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Withholding near-harvest irrigation in sweet cherry has minimal effect on fruit quality
Full text linkIrrigation management and fruit water relations play critical roles determining the quantity and quality of sweet cherry (Prunus avium L.) fruit as well as their susceptibility to rain-induced cracking. Fruit cracking remains a perennial challenge for growers despite decades of investigation. Indeed, neither empirical evidence nor anecdotal observations from commercial producers has yielded practicable irrigation management strategies for reducing fruit cracking. The objective of this study was therefore to investigate the role of near-harvest (i.e., during stage III of fruit development) irrigation on sweet cherry fruit quality and cracking susceptibility. Research trials were conducted by imposing preharvest irrigation termination in 2014 and 2015 in mature ‘Chelan’/Mazzard and ‘Lapins’/Mazzard commercial orchards. In both years and orchards, irrigation was targeted to be terminated by 20 or 10 days before harvest (DBH). Fruit yield, quality, and susceptibility to cracking, via a benchtop submersion test, were determined, comparing early irrigation termination treatments with the growers’ normal irrigation regimes (i.e., control). Soil water content, stem water potential, fruit and shoot growth rates were also recorded at ca. 3 day intervals between the onset of treatments and harvest. Fruit yield was unaffected by early irrigation termination, irrespective of cultivar. Fruit firmness of ‘Lapins’ was reduced by 6% in 2015 but both deficit treatments improved fruit soluble solids by more than 10%. In contrast, no irrigation treatment affected ‘Chelan’ fruit quality in either year. In addition, there was no consistent effect of irrigation treatment on fruit cracking index. In a separate trial, water movement through the vascular and exocarp pathways was studied on ‘Early Robin’ sweet cherry. Separate experiments evaluated the role of the pedicel on fruit cracking susceptibility, the transpiration capacity of fruit, and xylem water movement in fruit harvest at 3 Day intervals in the weeks before harvest. There was no apparent influence of the pedicel in cracking susceptibility. Transpiration estimates based on weight loss revealed a non-significant role of the pedicel up until harvest. In addition, fruit water import via the xylem did not vary with fruit maturity – it appears that water movement affecting cracking susceptibility is mainly due to water movement through the skin. Overall, withholding irrigation in the weeks prior to harvest does not consistently affect quality nor reduce cracking susceptibility
The Endogenous Formation of Coalitions to Provide Public Goods: Theory and Experimental Evidence
Full text linkThis paper examines the endogenous formation of coalitions that provide public goods in which players implement a minimum participation requirement before deciding whether to join. We demonstrate theoretically that payoff-maximizing players will vote to implement efficient participation requirements and these coalitions will form. However, we also demonstrate that if some players are averse to inequality they can cause inefficient outcomes. Inequality-averse players can limit free riding by implementing larger than efficient coalitions or by blocking efficient coalitions from forming. We test the theory with experimental methods and observe individual behavior and coalition formation consistent with a model of inequality-averse players. Key Words:
Post-Boot Feeding Effects by Bird-Cherry Oat and English Grain Aphids on Spring Wheat
No full textArtificial infestations of non-viruliferous bird-cherry oat, Rhopalosiphum padi (L.), and English grain aphids, Sitobion avenae (F.), were applied to spring wheat, Triticum aestivum (L.), under laboratory and field conditions. An aphid-free control and three levels of aphid infestation at 30, 60 and 120 aphids per plant were maintained and evaluated for differential plant responses to aphid feeding in the laboratory during phenological spring wheat growth stages of boot, anthesis and dough. Least significant difference analyses for bird-cherry oat aphid determined significant differences (P \u3c 0.01) among treatments concerning mature plant height, spikelet number, seed yield and total seed weight per head for the duration of boot. Observed trends suggest that aphid feeding influences have an additive effect for these variables. Significant differences (P \u3c 0.01) regarding variously maintained English grain aphid populations exhibited greater variability over growth stages with no defining trends in plant response. Simple linear regression techniques V revealed similar results with aphid populations unmaintained at identical departing aphid densities. Significant negative (P \u3c 0.01) slopes concerning R. padi were observed for seed yield and seed weight for the duration of boot. Non-significant relationships (P \u3e 0.05) were detected for English grain aphid regardless of growth stage with the exception of average seed weight (P \u3c 0.01) at boot. Artificial infestations of aphids produced varying population densities in a field cage study during late-boot through early-milk stages of crop development. Additional plots were infested with aphids at late-milk through hard-dough growth stages. Yield components including seed yield, number of heads, total seed weight and average seed weight were evaluated by multiple linear regression analyses. Significant negative linear slopes (P \u3c 0.01) regarding aphid populations of both species were determined for earlier development. Aphid feeding affected average seed weight most since aphid densities were designated as the primary regressor in r-square analyses. Non-significant (P \u3e 0.05) relations were found between aphid populations and yield components during late growth stages of spring wheat. Seed yield losses of 8.6% for R. padi at 37.5 aphids per tiller can be expected according to the model during late-boot through early-milk stages
Higher S-dualities and Shephard-Todd groups
Full text linkAbstract: Seiberg and Witten have shown that in N=2 SQCD with Nf = 2Nc = 4 the S-duality group PSL2ℤ acts on the flavor charges, which are weights of Spin(8), by triality. There are other N=2 SCFTs in which SU(2) SYM is coupled to strongly-interacting non-Lagrangian matter: their matter charges are weights of E6, E7 and E8 instead of Spin(8). The S-duality group PSL2ℤ acts on these weights: what replaces Spin(8) triality for the E6, E7, E8root lattices? In this paper we answer the question. The action on the matter charges of (a finite central extension of) PSL2ℤ factorizes trough the action of the exceptional Shephard-Todd groups G4 and G8 which should be seen as complex analogs of the usual triality group S3≃WeylA2. Our analysis is based on the identification of S-duality for SU(2) gauge SCFTs with the group of automorphisms of the cluster category of weighted projective lines of tubular type. © 2015, The Author(s)
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