126,871 research outputs found
Ak-Sar-Ben Beef Seminar Ill
No full textOpening Remarks - Mr. Robert G. Volk
Objectives of 4-H - Dr. William E. Caldwell
Moderator\u27s Remarks - Dr. Frank H. Baker
Carcass Characteristics of Various Breed Crosses — Dr. Robert Koch
Production Committee Report - Mr. Chuck Schroeder
Judges Committee Report - Dr. Miles McKee
Marketing and Distribution Report - Mr. Carl Gardner
Education Committee Report - Dr. Joe Hughes
Summary of Ak-Sar-Ben Beef Seminar III - Moderator
News Release on Ak-Sar-Ben Beef Seminar II
The underestimated virtues of the two-sector AK model
No full textWe show that the two-sector version of the AK model proposed by Rebelo (1991) can be read as an endogenous growth extension of Greenwood, Hercowitz and Krusell (1997). By confining constant returns to capital to the investment goods sector, the model generates endogenously the secular downward trend of the relative price of equipment investment and the rising real investment rate observed in US NIPA data. Whereas Jones (1995) criticizes that the one-sector model fails to reconcile the empirical facts of trending real investment rates and stationary output growth, this incompatibility vanishes in the two-sector version. Finally, a simple technological shock can reproduce the ‘1974’ break in post World War II US data. Thus, AK-type endogenous growth models comply much better with empirical evidence, once they are augmented with a strictly concave consumption sector.AK model; embodiment; endogenous growth; obsolescence; ‘1974’
Spatial dynamics and convergence: the spatial AK model
No full textWe study the optimal dynamics of an AK economy where population is uniformly distributed along the unit circle. Locations only differ in initial capital endowments. Despite constant returns to capital, we prove that transition dynamics will set in. In particular, we prove that the spatio-temporal dynamics, induced by the willingness of the planner to give the same (detrended) consumption over space and time, lead to convergence in the level of capital across locations in the long-run.Economic Growth, Inequality, Spatial Dynamics, Convergence
Spatial dynamics and convergence: the spatial AK model
No full textWe study the optimal dynamics of an AK economy where population is uniformly distributed along the unit circle. Locations only differ in initial capital endowments. Despite constant returns to capital, we prove that transition dynamics will set in. In particular, we prove that the spatio-temporal dynamics, induced by the willingness of the planner to give the same (detrended) consumption over space and time, lead to convergence in the level of capital across locations in the long-run.Economic Growth, Inequality, Spatial Dynamics, Convergence
More Lessons from Taking an AK Model to the Data.
No full textWe take an AK model to the PWT data. In the model both technology (intratemporal) and investment (intertemporal) shocks determine the variation of the growth rate. In earlier work we looked at singular models where we extracted only the technology shock using the policy functions from dynamic optimality. Here we recover time series for both shocks for a panel of countries and we isolate what we believe are pervasive patterns in macroeconomic models and postwar data: a negative correlation between intra and intertemporal shocks, and a somewhat lesser role for the intertemporal shock.endogenous growth; technology shocks; investment shocks
Economic And Environmental Impact Of The Tourism Carrying Capacity: A Local-Based Approach
No full textThe design and the evaluation of sustainable tourism policies require involving all the actors in the decision-making process. One of the critical aspects at the regional level is the absence of a clear definition of instruments and methodologies able to involve all the actors and to meet different policy targets. The aim of this study is to assess the economic and environmental impact of the tourism carrying capacity by proposing a framework able to deal with multiple variables. To this end, a social accounting matrix is built for a local area composed by four municipalities within the Sardinia region (Italy), and then it is used as a reference frame to implement the extended multisectoral model. Such an approach will provide results, on visitors flow recorded in the Asinara National Park, in terms of value added and CO2 emissions changes. © The Author(s) 2021
The Poverty of Linear Nations: Lessons from Taking an AK Model to the Data.
No full textThis paper takes an AK model to the PWT data. In the model, intratemporal and intertemporal shocks are reduced forms for different technologies, and determine the variation of the growth rate. Using the policy functions of the model we recover time series for the unobserved technology shock for a panel of countries. We can then evaluate both how well the model fits the data and what the contribution of the different shocks to the variation of growth rates is. We find that the data is largely inconsistent with the AK structure. However, we isolate what we believe are pervasive patterns in macroeconomic models: a negative correlation between intra and intertemporal shocks, and an ever increasing level of technology matched with ever cheaper consumption relative to investment.endogenous growth; technology shocks; investment shocks
Dynamic Programming, Maximum Principle and Vintage Capital
No full textWe present an application of the Dynamic Programming (DP) and of the Maximum Principle (MP) to solve an optimization over time when the production function is linear in the stock of capital (Ak model). Two views of capital are considered. In one, which is embraced by the great majority of macroeconomic models, capital is homogeneous and depreciates at a constant exogenous rate. In the other view each piece of capital has its own finite productive life cycle (vintage capital). The interpretation of the time patterns of macroaggregates is quite different between the two cases. A technological shock generates an oscillatory movement in the time pattern of per capita output when capital has a vintage structure; conversely an instantaneous adjustment with no transitional dynamics occurs when capital is homogeneous. From a methodological point of view it emerges that the DP approach delivers sharper results than the MP approach (for instance it delivers a closed form solution for the optimal investment strategy) under slacker parameter restrictions. Cross-time and cross-country data on investments, income, and consumption drawn from the Penn World Table version 6.2 are used to evaluate the vintage and standard Ak model.Vintage Capital; Penn World Table; Maximum Principle; Hilbert Space
Biological properties and HPLC analyses of four medicinal plants extracts obtained at different extraction temperatures
No full textIn the present study, extracts of four medicinal plants (Cajanus cajan, Carica papaya, Morinda morindoides, and Senna alexandrina) obtained at two different extraction temperatures (24 and 45°C) were investigated for their polyphenolic contents, antioxidant, and enzyme inhibitory properties. For instance, extracts of the studied species yielded total phenolic and flavonoid contents in the range of 17.8–66.3 mg GAE/g and 4.18–26.8 mg RE/g, respectively. High performance liquid chromatography (HPLC) coupled with antioxidant assays (HPLC-FRAP and HPLC-DPPH) was employed for direct identification of antioxidant compounds. The extracts showed moderate to high antioxidant potentials in various assays performed (radical scavenging activity: 10.15–240.08 mg TE/g; reducing activity: 24.88–229.59 mg TE/g; metal chelating activity: 5.56–18.32 mg EDTAE/g and total antioxidant capacity: 1.40–2.18 mM TE/g). Additionally, the extracts were found to exert inhibitory properties against all the studied enzymes (anti-acetylcholinesterase: 1.80–2.29 mg GALAE/g; anti-butyrylcholinesterase: 0.19–3.13 mg GALAE/g; anti-amylase: 0.39–0.58 mmol ACAE/g; anti-glucosidase: 0.17–1.36 mmol ACAE/g and anti-tyrosinase: 60.97–73.71 mg KAE/g). Of all, C. cajan extracts were revealed to be the best antioxidants and inhibitors of most enzymes. Therefore, this study demonstrated the pharmacological potentials of the four medicinal plants, especially C. cajan as viable sources of phyto-ingredients that could be of interest in nutraceutical development. Novelty impact statement: The methanol extracts from four medicinal plant with different extraction temperatures (24 and 45°C) were investigated. HPLC-DPPH and HPLC-FRAP methodologies were used. Different levels of phenolics in the tested extracts were determined. Cajamus cajan extracts were found to be the best one in the antioxidant assays. Our findings could be opened valuable windows in the further pharmaceutical studies and applications
Chemodiversity and biological activity of essential oils from three species from the Euphorbia genus
No full textSeveral studies demonstrated the wide pharmacological properties of extracts and essential oils (EOs) prepared from Euphorbia species. In the present study, the chemical composition and biological activities of EOs from three different Euphorbia species were evaluated using in vitro methods. A total of 29, 33 and 42 constituents were identified in the EOs of E hirta, E convolvuloides and E heterophylla, respectively. The EOs exhibited in vitro radical scavenging potential in the ABTS assay (2.89-21.50 mg/g). Additionally, an inhibitory effect on acetylcholinesterase (4.23-5.12 mg/g) was detected. Besides, remarkable tyrosinase inhibition was reported by the EOs (95.24-113.74 mg/g). Molecular docking was also performed to elucidate the binding interactions between selected EO components and enzymes. Phytol and geranyl-(E)-acetone had a good binding with tyrosinase in the molecular docking. This study highlighted the promising pharmacological profiles of these EOs as natural sources of antioxidants as well as cholinesterase and tyrosinase inhibitors that could be further explored in the management of human ailments in food and pharmaceutical industries
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