55 research outputs found
Agreeable Smellers and Sensitive Neurotics â Correlations among Personality Traits and Sensory Thresholds
Correlations between personality traits and a wide range of sensory thresholds were examined. Participants (Nâ=â124) completed a personality inventory (NEO-FFI) and underwent assessment of olfactory, trigeminal, tactile and gustatory detection thresholds, as well as examination of trigeminal and tactile pain thresholds. Significantly enhanced odor sensitivity in socially agreeable people, significantly enhanced trigeminal sensitivity in neurotic subjects, and a tendency for enhanced pain tolerance in highly conscientious participants was revealed. It is postulated that varied sensory processing may influence an individual's perception of the environment; particularly their perception of socially relevant or potentially dangerous stimuli and thus, varied with personality
Optimum harvest time in Aquaculture: an application of economic principles to a Nile tilapia, Oreochromis niloticus (L.), growth model
A simple method is presented for determining the optimum time to harvest fish and the effect of fertilization type on optimum harvest time for Aquaculture. Optimum harvest time was similar for either maximizing fish yield or maximizing profit of fish harvested (price of fish times fish yield minus fish production cost), because the daily change in fish production cost was low for the low-input Nile tilapia, Oreochromis niloticus (L.), production system in Thailand. At a harvest time of 150 days for an organic fertilization treatment compared to an inorganic fertilization treatment fish yield increased from l-505 t/ha to 2-295 t/ha, and profit of fish harvested increased from 15657¡1 baht/ha (US 948-2/ha). For the organic treatment, optimum harvest time occurred at 191 days, with a fish yield of 2¡328 t/ha and a profit of 25520¡5baht/ha (US 605¡1/ha).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73931/1/j.1365-2109.1992.tb00807.x.pd
Bioeconomic Model of Rainbow Trout (\u3cem\u3eOncorhynchus mykiss\u3c/em\u3e) and Humpback Chub (\u3cem\u3eGila cypha\u3c/em\u3e) Management in the Grand Canyon
The Colorado River, from Glen Canyon Dam (GCD) to the Little Colorado River (LCR) confluence, includes both non-native Rainbow Trout (Oncorhynchus mykiss) and endangered native Humpback Chub (Gila cypha). While both Rainbow Trout and Humpback Chub are valued fish species in this system, Rainbow Trout can have a negative effect on Humpback Chub survival. We developed a bioeconomic model to determine management actions that minimize the costs of controlling Rainbow Trout abundance subject to achieving Humpback Chub population goals. The model is compartmentalized into population and management components. The population component characterizes the stylized dynamics of Rainbow Trout and Humpback Chub from GCD to the LCR confluence within the Colorado River. The management component of the model identifies Rainbow Trout mechanical removal strategies that achieve average annual juvenile Humpback Chub survival targets while minimizing management costs. This research is an interdisciplinary effort combining biological models and economic methods to address federal, state and tribal stakeholder resource goals related to Rainbow Trout and Humpback Chub management in this complex social-ecological system
Political economy of renewable resource federalism
Author Posting. Š Ecological Society of America, 2021. 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 00 (2021): e2276, doi:10.1002/eap.2276.The authority to manage natural capital often follows political boundaries rather than ecological. This mismatch can lead to unsustainable outcomes, as spillovers from one management area to the next may create adverse incentives for local decision making, even within a single country. At the same time, oneâsizeâfitsâall approaches of federal (centralized) authority can fail to respond to state (decentralized) heterogeneity and can result in inefficient economic or detrimental ecological outcomes. Here we utilize a spatially explicit coupled naturalâhuman system model of a fishery to illuminate tradeâoffs posed by the choice between federal vs. state control of renewable resources. We solve for the dynamics of fishing effort and fish stocks that result from different approaches to federal management that vary in terms of flexibility. Adapting numerical methods from engineering, we also solve for the openâloop Nash equilibrium characterizing state management outcomes, where each state anticipates and responds to the choices of the others. We consider traditional federalism questions (state vs. federal management) as well as more contemporary questions about the economic and ecological impacts of shifting regulatory authority from one level to another. The key mechanisms behind the tradeâoffs include whether differences in local conditions are driven by biological or economic mechanisms; degree of flexibility embedded in the federal management; the spatial and temporal distribution of economic returns across states; and the statusâquo management type. While simple rulesâofâthumb are elusive, our analysis reveals the complex political economy dimensions of renewable resource federalism.This work was partially supported through the Ecological Federalism working group of the National Institute for Mathematical and Biological Synthesis, an Institute sponsored by the National Science Foundation through NSF Award (No. DBIâ1300426), with additional support from the Howard H. Baker Jr. Center for Public Policy and The University of Tennessee, Knoxville. M. G. Neubert acknowledges support from the U.S. National Science Foundation (DEBâ1558904) and from the J. Seward Johnson Endowment in support of the Woods Hole Oceanographic Institutionâs Marine Policy Center. We would like to thank seminar participants at Oregon State University, Nature Policy Lab at U.C. Davis, and the 2019 Association of Environmental and Resource Economists Summer Conference for valuable comments and suggestions on earlier versions of this research
There is no triangulation of the torus with vertex degrees 5, 6, ..., 6, 7 and related results: Geometric proofs for combinatorial theorems
There is no 5,7-triangulation of the torus, that is, no triangulation with
exactly two exceptional vertices, of degree 5 and 7. Similarly, there is no
3,5-quadrangulation. The vertices of a 2,4-hexangulation of the torus cannot be
bicolored. Similar statements hold for 4,8-triangulations and
2,6-quadrangulations. We prove these results, of which the first two are known
and the others seem to be new, as corollaries of a theorem on the holonomy
group of a euclidean cone metric on the torus with just two cone points. We
provide two proofs of this theorem: One argument is metric in nature, the other
relies on the induced conformal structure and proceeds by invoking the residue
theorem. Similar methods can be used to prove a theorem of Dress on infinite
triangulations of the plane with exactly two irregular vertices. The
non-existence results for torus decompositions provide infinite families of
graphs which cannot be embedded in the torus.Comment: 14 pages, 11 figures, only minor changes from first version, to
appear in Geometriae Dedicat
Discrete conformal maps: boundary value problems, circle domains, Fuchsian and Schottky uniformization
We discuss several extensions and applications of the theory of discretely conformally equivalent triangle meshes (two meshes are considered conformally equivalent if corresponding edge lengths are related by scale factors attached to the vertices). We extend the fundamental definitions and variational principles from triangulations to polyhedral surfaces with cyclic faces. The case of quadrilateral meshes is equivalent to the cross ratio system, which provides a link to the theory of integrable systems. The extension to cyclic polygons also brings discrete conformal maps to circle domains within the scope of the theory. We provide results of numerical experiments suggesting that discrete conformal maps converge to smooth conformal maps, with convergence rates depending on the mesh quality. We consider the Fuchsian uniformization of Riemann surfaces represented in different forms: as immersed surfaces in \mathbb {R}^{3}, as hyperelliptic curves, and as \mathbb {CP}^{1} modulo a classical Schottky group, i.e., we convert Schottky to Fuchsian uniformization. Extended examples also demonstrate a geometric characterization of hyperelliptic surfaces due to Schmutz Schaller
Alternative futures for global biological invasions
Scenario analysis has emerged as a key tool to analyze complex and uncertain future socio-ecological developments. However, currently existing global scenarios (narratives of how the world may develop) have neglected biological invasions, a major threat to biodiversity and the economy. Here, we use a novel participatory process to develop a diverse set of global biological invasion scenarios spanning a wide range of plausible global futures through to 2050. We adapted the widely used âtwo axesâ scenario analysis approach to develop four families of four scenarios each, resulting in 16 scenarios that were later clustered into four contrasting sets of futures. Our analysis highlights that socioeconomic developments and technological innovation have the potential to shape biological invasions, in addition to well-known drivers, such as climate and human land use change and global trade. Our scenarios partially align with the shared socioeconomic pathways created by the climate change research community. Several factors that drive differences in biological invasions were underrepresented in the shared socioeconomic pathways; in particular, the implementation of biosecurity policies. We argue that including factors related to public environmental awareness and technological and trade development in global scenarios and models is essential to adequately consider biological invasions in global environmental assessments and thereby obtain a more integrative picture of future socialâecological developments
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