1,507 research outputs found
COMMENT: EFFICIENCY OF ITQS IN THE PRESENCE OF PRODUCTION EXTERNALITIES
Resource /Energy Economics and Policy,
Using Participation Data to Estimate Fishing Costs for Commercial Salmon Fisheries in Alaska
This paper estimates the fishing costs and the returns to fishing for nine commercial salmon fleets in Alaska. The econometric model uses a two-stage least squares estimation procedure to estimate the effect of congestion and heterogeneity on the returns to fishermen. The hypotheses that fishermen are homogenous and that there is no congestion externality present in the fisheries are strongly rejected. The data indicates that fishermen are quite heterogeneous in fishing skill levels. This difference accounts for the overall estimates of positive net returns to the common property fisheries. Estimates of the net returns to the fisheries suggest that the returns to different gear types vary largely. The set net fleets are found to have the highest return as a percentage of total revenues.Fishing costs, econometric model, heterogeneity, skill rents, commercial salmon fisheries, Environmental Economics and Policy, Production Economics,
Good Fences Make Good Neighbors: Endogenous Property Rights in a Game of Conflict
This paper derives the conditions under which property rights can arise in an anarchy equilibrium. The creation of property rights requires that players devote part of their endowment to the public good of property rights protection. In the Nash equilibrium, players contribute zero to the protection of property rights. In contrast, a king who provides property rights protection paid for by a tax on endowments can completely eliminate conflict, but such a king has an incentive to take the surplus for himself. Thus players have an incentive to find a solution that keeps power in their own hands. In a social contract, players first credibly commit part of their endowments to providing property rights and then allocate the balance of their endowments between production and conflict. While property rights can arise under a social contract if the productivity of resources relative to the size of the population is sufficiently high, these property rights may be less than perfectly secure. Nevertheless, for sufficiently high productivity of resources relative to the size of the population, the social contract welfare dominates autocracy. Key Words:
Syntheses of (+)-30-epi-, (-)-6-epi-, (±)-6,30-epi-13,14-didehydroxyisogarcinol and (±)-6,30-epi-garcimultiflorone A utilizing highly diastereoselective, Lewis acid-controlled cyclizations
The first syntheses of 13,14-didehydroxyisogarcinol (6) and garcimultiflorone A (5) stereoisomers are reported in six steps from a commercially available phloroglucinol. Lewis acid-controlled, diastereoselective cationic oxycyclizations enabled asymmetric syntheses of (-)-6-epi-6 and (+)-30-epi-6. A similar strategy enabled production of the meso-dervied isomers (±)-6,30-epi-6 and (±)-6,30-epi-5. Finally, a convenient strategy for gram scale synthesis was developed utilizing diastereomer separation at a later stage in the synthesis that minimized the number of necessary synthetic operations to access all possible stereoisomers.R01 GM073855 - NIGMS NIH HHS; R24 GM111625 - NIGMS NIH HHS; R35 GM118173 - NIGMS NIH HH
Surface Properties Of The Arterial Wall And Their Relevance To Atherosclerosis
Adhesion of platelets to the arterial subendothelium exposed by injury to the endothelium, is thought to initiate atherosclerosis. Thermodynamically, adhesion will occur if it decreases the free energy of the system. Here, I have developed a contact angle technique to measure relative changes in the interfacial free energy of the arterial wall, before and after removal of the endothelium. Sections of aorta were tested with an equilibrium two phase system of 4% poly (ethylene glycol) (PEG)/4% dextran, in buffered physiological saline. The tissue was immersed in the PEG phase and droplets of the denser dextran phase were placed on its lumenal surface. After testing, the endothelium was removed with a saline jet, and the tissue was retested. Contact angles of 86.0 (+OR-) 1.1(DEGREES) (SEM), n = 64 for the intact endothelium, and 20.0 (+OR-) 0.08 (SEM), n = 61 on the subendothelium, were measured from photomicrographs. Since the physical behavior of blood is similar to the PEG phase, the subendothelium probably represents a high energy surface in vivo, thus promoting platelet adhesion.;Factors which cause endothelial injury may act chronically at the cell surface to cause desquamation. To test this hypothesis, rabbits fed a 2% cholesterol diet to induce atherosclerosis were divided into 3 experimental groups: continuous feeding, interrupted feeding, and controls. Areas proximal and distal to intercostal orifices, where no plaque had yet developed, were tested with the PEG/dextran system. Proximal areas on the diseased arteries, and both the proximal and distal locations in controls gave contact angles of approximately 90(DEGREES); however those areas distal to orifices, where lesions eventually occur, yielded significantly different angles, 78(DEGREES). This difference indicates a change in the glycocalyx, which could weaken the cell resistance to injury, leading to desquamation, platelet adhesion and plaque formation
Effects of Apolipoprotein E, Sex, and Estrogen on the Neuroplasticity of Olfactory Receptor Neurons in Mice Following Olfactory Bulbectomy
Apolipoprotein E (apoE) is well studied for its role in cholesterol transportation and metabolizing lipoproteins. ApoE is found in the olfactory system especially in the olfactory nerve and glomeruli of the olfactory bulb. Studies from our laboratory indicate that apoE is a required component for timely regeneration and olfactory receptor neuron maturation. The mechanism for which apoE contributes to neuron function and developing late onset Alzheimer\u27s disease is still being studied. A mutant form of apoE (apoE 4) is believed to be a prominent genetic risk factor for this neurodegenerative disease. Over sixty percent of Alzheimer\u27s disease patients in the United Sates are women. This revelation has concentrated more focus on the loss of estrogen as a potential risk factor. To better understand how apoE and estrogen may contribute to Alzheimer\u27s disease, this study utilizes apoE knockout mice and estradiol treatment.
Using the olfactory system as a model, the right olfactory bulb was removed from all treatments of wild type (WT) and apoE knockout (KO) mice. Retrograde olfactory receptor neuron death and regeneration was observed between males and females of both genotypes in the olfactory epithelium. The results show massive olfactory receptor neuron death within days of olfactory bulb ablation in male mice compared to their female counter part. When estrogen was given at above the physiological dose, the duration of neuroprotection increased. However, when no estrogen was present olfactory receptor neurons died faster. Overall, mice treated with estrogen exhibited a more rapid rate of regeneration regardless of the presence of apoE.
Animals without apoE illustrated similar results to those with apoE but the average data values were slightly lower for apoE knockout mice than WTmice, illustrating that apoE is required for proper olfactory epithelium maintenance. These results were fairly consistent 4 throughout the data; however data for estradiol treated animals varied among genotypes. To measure the rate of olfactory receptor neuron death olfactory epithelium thickness was measured at 3, 7 and 21 days following olfactory bulbectomy. To observe the rate of death of mature olfactory receptor neurons olfactory marker protein (OMP) immunohistochemistry was performed. To gauge the rate of globose basal (stem) cell division bromodeoxyuridine (BrdU) immunohistochemistry was performed. By removing the olfactory bulb, the target for olfactory receptor neuron which served as the signal transduction, the olfactory epithelium fails to return to its original thickness suggesting olfactory receptor neuron maturity is dependent on proper target connectivity
Effects of Apolipoprotein E, Sex, and Estrogen on the Neuroplasticity of Olfactory Receptor Neurons in Mice Following Olfactory Bulbectomy
Apolipoprotein E (apoE) is well studied for its role in cholesterol transportation and metabolizing lipoproteins. ApoE is found in the olfactory system especially in the olfactory nerve and glomeruli of the olfactory bulb. Studies from our laboratory indicate that apoE is a required component for timely regeneration and olfactory receptor neuron maturation. The mechanism for which apoE contributes to neuron function and developing late onset Alzheimer\u27s disease is still being studied. A mutant form of apoE (apoE 4) is believed to be a prominent genetic risk factor for this neurodegenerative disease. Over sixty percent of Alzheimer\u27s disease patients in the United Sates are women. This revelation has concentrated more focus on the loss of estrogen as a potential risk factor. To better understand how apoE and estrogen may contribute to Alzheimer\u27s disease, this study utilizes apoE knockout mice and estradiol treatment.
Using the olfactory system as a model, the right olfactory bulb was removed from all treatments of wild type (WT) and apoE knockout (KO) mice. Retrograde olfactory receptor neuron death and regeneration was observed between males and females of both genotypes in the olfactory epithelium. The results show massive olfactory receptor neuron death within days of olfactory bulb ablation in male mice compared to their female counter part. When estrogen was given at above the physiological dose, the duration of neuroprotection increased. However, when no estrogen was present olfactory receptor neurons died faster. Overall, mice treated with estrogen exhibited a more rapid rate of regeneration regardless of the presence of apoE.
Animals without apoE illustrated similar results to those with apoE but the average data values were slightly lower for apoE knockout mice than WTmice, illustrating that apoE is required for proper olfactory epithelium maintenance. These results were fairly consistent 4 throughout the data; however data for estradiol treated animals varied among genotypes. To measure the rate of olfactory receptor neuron death olfactory epithelium thickness was measured at 3, 7 and 21 days following olfactory bulbectomy. To observe the rate of death of mature olfactory receptor neurons olfactory marker protein (OMP) immunohistochemistry was performed. To gauge the rate of globose basal (stem) cell division bromodeoxyuridine (BrdU) immunohistochemistry was performed. By removing the olfactory bulb, the target for olfactory receptor neuron which served as the signal transduction, the olfactory epithelium fails to return to its original thickness suggesting olfactory receptor neuron maturity is dependent on proper target connectivity
Training the Trainers in Community-Based Rehabilitation
Queen’s University and the Pan-American Health Organization are collaborating on a project called Community-Based Rehabilitation, designed to aid survivors. The project assists victims with their physical, emotional and financial problems to help them reenter and remain active in their communities
Application and use of spinal immobilization devices in zero-gravity flight
A KC-135 parabolic flight was performed for the purpose of evaluation of spinal immobilization techniques in microgravity. The flight followed the standard 40 parabola profile with four NASA/KRUG experimenters involved. One performed as coordinator/recorder, one as test subject, and two as the Crew Medical Officers (CMO). The flight was to evaluate the application of spinal immobilization devices and techniques in microgravity as are performed during initial stabilization or patient transport scenarios. The sequence of detail for examination of the following objectives included: attempted cervical spine immobilization with all free floating, the patient restrained to the floor, various hand positioning techniques; c-collar placement; Kendrick Extrication Device (KED) application with various restraints for patient and CMO; patient immobilization and transport using the KED; patient transported on KED and spine board. Observations for each task are included. Major conclusions and issues are also included
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