A Shapley Value Analysis to Coordinate the Formation of Procurement Networks

In this paper we address the problem of forming procurement networks for items with value adding stages that are linearly arranged. Formation of such procurement networks involves a bottom-up assembly of complex production, assembly, and exchange relationships through supplier selection and contracting decisions. Research in supply chain management has emphasized that such decisions need to take into account the fact that suppliers and buyers are intelligent and rational agents who act strategically. In this paper, we view the problem of procurement network formation (PNF) for multiple units of a single item as a cooperative game where agents cooperate to form a surplus maximizing procurement network and then share the surplus in a fair manner. We study the implications of using the Shapley value as a solution concept for forming such procurement networks. We also present a protocol, based on the extensive form game realization of the Shapley value, for forming these networks.

The environmental and economic sustainability of potential bioethanol from willow in the UK.

Life cycle assessment has been used to investigate the environmental and economic sustainability of a potential operation in the UK in which bioethanol is produced from the hydrolysis and subsequent fermentation of coppice willow. If the willow were grown on idle arable land in the UK, or, indeed, in Eastern Europe and imported as wood chips into the UK, it was found that savings of greenhouse gas emissions of 70-90%, when compared to fossil-derived gasoline on an energy basis, would be possible. The process would be energetically self-sufficient, as the co-products, e.g. lignin and unfermented sugars, could be used to produce the process heat and electricity, with surplus electricity being exported to the National Grid. Despite the environmental benefits, the economic viability is doubtful at present. However, the cost of production could be reduced significantly if the willow were altered by breeding to improve its suitability for hydrolysis and fermentation.

Política económico-social : cambio es desde 2011

"Una economía en crecimiento: la década del ‘2000. A partir de la crisis de 2001, una serie de medidas como la fuerte devaluación del peso, la pesificación asimétrica, la pesificación de los contratos de empresas de servicios públicos y congelamiento de tarifas, y el default de la deuda pública fueron dando forma a una nueva organización económica. Un tipo de cambio muy depreciado y la sorprendente suba del precio de los commodities permitieron una recuperación de la producción y del crecimiento, si bien las exportaciones crecieron por tirón de demanda externa, particularmente desde Asia Pacífico. Otra medida fue reinstalar las retenciones a las exportaciones (2002) y se realizó el canje de deuda pública (2005). Se generaron los superávit gemelos que otorgaron credibilidad para las decisiones de inversión. La inflación se mantuvo controlada, sin passing through relevante y sin indexaciones salariales. La recuperación del empleo privado por la reactivación y la parcial sustitución de importaciones, más el efecto competitividad del tipo de cambio depreciado, junto a los planes sociales mejoraron la situación social..."

Local exchange in the southern levant during the early bronze age: a political economy viewpoint

Trade and relations between the southern Levant and other regions of the Near East (mainly Egypt) during the Early Bronze Age (ca. 3,600–2,300 BC) have been the subject of many studies. Research concerning the exchange of local commodities was almost ignored or was discussed in parochial studies, focusing on specific archaeological finds. It is the intention of this paper to present the results of recent research of the exchange of commodities provided by archaeological data from excavations in the Southern Levant with regard to economic theories on the exchange-value of goods and exchange networks. Conclusions regarding the type of society and the forms of government in the Southern Levant during the Early Bronze Age are also presented.

Fiscal imbalances, inflation and sovereign default dynamics

Resumen: La cuestión central que este artículo busca responder es como la política monetaria puede afectar el comportamiento de equilibrio de primas por riesgo soberano y cesación de pagos. El artículo se basa en el modelo de “una-tasa-interés”. La deuda pública se hace riesgosa a causa de una política fiscal activa, como en Uribe (2006), reflejando la habilidad limitada de la autoridad fiscal para controlar el superávit primario. El problema de insolvencia es debido a una oleada de mala suerte (shocks negativos que afectan el superávit primario). Pero en contraste a los resultados de Uribe, a medida que aumenta el costo de la deuda soberana (que resulta de un excedente primario débil), la cesación de pagos se anticipa y es reflejada por una creciente prima de riesgo en el país y una probabilidad de cesación de pagos. La cesación de pagos se define como un incumplimiento de un acuerdo contractual y por ende la decisión es tomada por la autoridad fiscal. Mientras tanto, objetivos conflictivos entre la autoridad monetaria y fiscal juegan un rol importante en llevar a la autoridad fiscal a la cesación de pagos sobre sus pasivos. La característica de la política del gobierno necesaria para restaurar el equilibrio después de la cesación de pagos también es analizada.

Teoría de la plusvalía en Marx

Resumen: El artículo presenta un recorrido por algunos de los postulados de la economía británica clásica, a fin de comprender acabadamente la teoría de la plusvalía de Carlos Marx. Así, el autor analiza algunos conceptos fundamentales para tal efecto. Define –entrecruzando los postulados de Adam Smith y David Ricardo– las nociones de: el valor de las cosas, el precio de los salarios, y el beneficio empresario. Luego, dedica una sección a describir las críticas de Adam Smith y Carlos Marx al capitalismo. Desarrolla cabalmente lo relativo a la obtención y magnitud de la plusvalía, y realiza una reflexión final que define a la teoría de la plusvalía como conceptualmente falsa.

The scientific project of the small satellite of china

The efforts involved in developing a small satellite for scientific purposes in China in recent years are introduced in the present paper. The project is arranged on a case to case principle depending upon requirements and financial support. The space technology of a satellite and rockets, which have been developed over a relatively longer period in China, have been transferred to the scientific research of small satellites for improvement of the quality requirements. The surplus payloads of the rocket and satellite are used as the payloads of the small satellite and scientific experiments at a low cost. As an example, the project of balloon satellites for atmospheric research was successfully completed in 1991. The experience of the project management is of great benefit for further organization and arrangement of other projects. Opportunities exist for surplus payloads to be used in the future, and a small satellite for magnetospheric research will be launched in 1993.

A Fundamental Contradiction in Standard Rent Theory: A Case Study on Varian's "Intermediate Microeconomics"

In this paper, I examine Varian’s treatment of rent in his textbook on Microeconomics. I argue that he holds contradictory conceptions: sometimes rent is defined as surplus over cost whereas sometimes it is defined as cost, as the opportunity cost of fixed factors. I start by arguing that the distinction between fixed and variable factors is not the key for the definition of rent; ultimately, it is monopoly. Varian’s conception of rent is, essentially, Ricardo’s: rent is extraordinary profit turned rent. On the basis of a selfinconsistent notion of opportunity cost, Varian introduces the idea that rent is the opportunity cost of land, when what he actually defines is the opportunity cost of not renting the land. I also critically examine the related notion of “producer’s surplus”, and show that Varian’s treatment repeats the same contradiction as in rent.

Does Immigration Raise Natives’ Income? National and Regional Evidence from Spain

How immigration affects the labor market of the host country is a topic of major concern for many immigrant-receiving nations. Spain is no exception following the rapid increase in immigrant flows experienced over the past decade. We assess the impact of immigration on Spanish natives’ income by estimating the net immigration surplus accruing at the national level and at high immigrant-receiving regions while taking into account the imperfect substitutability of immigrant and native labor. Specifically, using information on the occupational densities of immigrants and natives of different skill levels, we develop a mapping of immigrant-to-native self-reported skills that reveals the combination of natives across skills that would be equivalent to an immigrant of a given self-reported skill level, which we use to account for any differences between immigrant self-reported skill levels and their effective skills according to the Spanish labor market. We find that the immigrant surplus amounts to 0.04 percent of GDP at the national level and it is even higher for some of the main immigrant-receiving regions, such as Cataluña, Valencia, Madrid, and Murcia.

Policy Coordination in an Oligopolistic Housing Market

This paper analyzes the consequences of the interaction between two different levels of government (regulators) in the development of housing policy when their decisions determine the level of competition in the housing market. The analysis discusses the implications derived from a lack of coordination between a local regulator who controls the supply of land for housing development and a central regulator who decides on housing subsidies. The results suggest that lack of coordination has significant effects on prices and supply of houses, housing developers’ profits, and buyers’ surplus.

Ad valorem housing subsidies may reduce house building

In this paper it is shown that an ad valorem housing subsidy set by a central regulator (or a raise in the ad valorem housing subsidy rate) may reduce the number of houses built in the market and increase the price paid by the buyers of houses. The analysis considers a situation where there is imperfect competition in the housing market and a local regulator that decides on density, or on the number of sites for housing development, and that cares about a combination of the profits of housing developers and the surplus of buyers of houses.

Assessment of cobia, Rachycentron canadum, in the waters of the U.S. Gulf of Mexico

This assessment applies to cobia (Rachycentron canadum) located in the territorial waters of the U.S. Gulf of Mexico. Separation of the Gulf of Mexico and Atlantic Ocean is defined by the seaward extension of the Dade/Monroe county line in south Florida. Mixing of fish between the Atlantic and Gulf of Mexico occurs in the Florida Keys during winter months. Cobia annually migrate north in early spring in the Gulf to spawning grounds in the northern Gulf of Mexico, returning to the Florida Keys by winter. Catches of cobia in the Gulf of Mexico are dominated by recreational landings, accounting for nearly 90% of the total. Since 1980, the landings of cobia in the recreational fishery have remained fairly stable at around 400-600 mt with a slight peak of 1,014 mt in 1997. The recreational fishery was estimated to have landed 471 mt in 2000. The landings from the commercial fishery have shown a steady increase from 45 mt in 1980 to a peak of 120 mt in 1994, followed by a decline to 62 mt in 2000. The previous assessment of cobia occurred in 1996 using a virtual population analysis (VPA) model. For this analysis a surplus-production model (ASPIC) and a forward-projecting, age-structured population model programmed in the AD Model Builder (ADMB) software were applied to cobia data from the Gulf of Mexico. The primary data consisted of four catch-per-unit-effort (CPUE) indices derived from the Marine Recreational Fisheries Statistics Survey (MRFSS) (1981-1999), Southeast region headboat survey (1986-1999), Texas creel survey (1983-1999), and shrimp bycatch estimates (1980-1999). Length samples were available from the commercial (1983-2000) and recreational (1981-2000) fisheries. The ASPIC model applied to the cobia data provided unsatisfactory results. The ADMB model fit described the observed length composition data and fishery landings fairly well based on graphical examination of model residuals. The CPUE indices indicated some disagreement for various years, but the model fit an overall increasing trend from 1992-1997 for the MRFSS, headboat, and Texas creel indices. The shrimp bycatch CPUE was treated as a recruitment index in the model. The fit to these data followed an upward trend in recruitment from 1988-1997, but did not fit the 1994-1997 data points very well. This was likely the result of conflicting information from other data sources. Natural mortality (M) for cobia is unknown. As a result, a range of values for M from 0.2-0.4, based on longevity and growth parameters, were selected for use in the age-structured model. The choice of natural mortality appears to greatly influence the perceived status of the population. Population status as measured by spawning stock biomass in the last year relative to the value at maximum sustainable yield (SSB2000/SSBMSY), spawning stock biomass in the last year relative to virgin spawning stock biomass (SSB2000/S0), and static spawning stock biomass per recruit (SSBR) all indicate the population is either depleted, near MSY, or well above MSY depending on the choice of M. The variance estimates for these benchmarks are very large and in most cases ranges from depleted to very healthy status. The only statement that can be made with any degree of certainty about cobia in the Gulf of Mexico is that the population has increased since the 1980s. (PDF contains 61 pages)

Impact of the commercial fishery on the population of bait shrimp (Penaeus spp.) in Biscayne Bay, 1986

Monthly population size of bait shrimp in the Bay was estimated from December 1984 to July 1985. Growth rates for male and female P. duorarum showed that pink shrimp exhibit a mean residence time in the nursery area (Biscayne Bay) of approximately 21 weeks. Monthly mortality rates were determined for each sex of pink shrimp. It was estimated that 23% and 26% of the male and female monthly population size, respectively, was absorbed by both the fishery and ecosystem monthly. Monthly proportion of the standing stock expected to die exclusively through fishing was 6.5% and 6.0% for males and females respectively. Estimates of emigration rates showed that approximately 4.0% of the population was lost from the Bay system each month. This surplus production was about 50% of the average monthly catch by the fleet. Fishing mortality represents only 8 - 9% of the losses to the shrimp population. The biggest source of loss is emigration, suggesting that most shrimp beyond the size at recruitment (to the fishery) are not utilized for food while in the Bay. Thus, it appears that the direct impact of the fishery on the bait shrimp population is relatively small. (PDF contains 46 pages)

Stock assessment of the Atlantic menhaden, Brevoortia tyrannus, fishery

A stock assessment of the Atlantic menhaden, Brevoortia tyrannus, fishery was conducted with purse-seine landings data from 1940 to 1984 and port sampling data from 1955 to 1984. These data were analyzed to determine growth rates, maximum sustainable yield (MSY), spawner-recruit relationships, and yield per recruit. Virtual population analysis was used to estimate stock size, year class size, and fishing mortality rates. Surplus production models produced estimates of MSY from 450 to 490 kmt compared with yields of 416to 436 kmt based roughly on maximum recruitment from a weak spawner-recruit relationship. Recruitment to age-I ranged from 1.2 to 14.8 billion fish for year classes 1955-81. Recent mean recruitment to age-I for the 1975-81 year classes averaged 5.7 billion fish and compared favorably with the mean of 7.7 billion age-I fish recruited during the late 1950's. Mean recruitment from recent years suggests possible coastwide yields of 416 to 481 kmt. Continued dominance of late age-2 spawners among the spawning stock is of concern, since the stock is at greater risk through poor recruitment if recent favorable environmental conditions change. Yield-per-recruit estimates ranged from 46 g to 59 g since 1970. The high dependency of the modern fishery on prespawners has increased concerns about fluctuations in year-to-year availability and catches. To increase yield and enhance the stability of the resource, the number of age classes contributing significantly to the fishery should be increased, creating a butTer against future poor recruitment years and lessening the year-to-year fluctuations in landings. (PDF file contains 24 pages.)

Stock assessment of the gulf menhaden, Brevoortia patronus, fishery

A stock assessment of the gulf menhaden. Brevoortia patronus, fishery was conducted with data on purse-seine landings from 1946 to 1985 and port sampling data from 1964 to 1985. These data were analyzed to determine growth rates, yield-per-recruit, spawner-recruit relationships, and maximum sustainable yield (MSY). Virtual population analysis was used to estimate stock size, year-class size, and fishing mortality rates. During the period studied, an average of 27% of age-l fish and 55% of age-2 and age-3 fish were taken by the fishery, and 54% for age-I and 38% for age-2 and -3 fish were lost annually to natural causes. Annual yield-per-recruit estimates ranged from 6.9 to 19.3 g, with recent mean conditions averaging 12.2 g since 1978. Surplus production models produced estimates of MSY from 620 to 700 kilometric tons. Recruits to age-I ranged from 8.3 to 41.8 billion fish for 1964-82. Although there was substantial scatter about the fitted curves, Ricker·type spawner-recruit relationships were found suitable for use in a population simulation model. Estimates of MSY from population simulation model runs ranged from 705 to 825 kilometric tons with F -multiples of the mean rate of fishing ranging from 1.0 to 1.5. Recent harvests in excess of the historical MSY may not be detrimental to the gulf menhaden stock. However, one should not expect long-term harvesting above the historical MSY because of the short life span of gulf menhaden and possible changes from currently favorable environmental conditions supporting high recruitment.(PDF file contains 24 pages.)