bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Productivity of Public Forests: A Stochastic Frontier Analysis of Mississippi School Trust Timber Production
Authors: Bonds Matthew H. , Hughes Danny R. 
Published: May 2007

This paper presents the results of a stochastic frontier analysis on the technical efficiency of school trust timber production in Mississippi. The state of Mississippi has a 200‐year history of managing public trust lands designated to generate funds for public schools. Local school boards became the trustees of sixteenth section lands in the 1970s and have since supervised substantial increases in timber receipts. The majority of the timber management services are contracted to the Mississippi Forestry Commission (MFC)—a state agency responsible for, among other things, overseeing sixteenth section timber management. The school districts and the MFC are legally required to maximize revenue from these lands. However, school districts are also legally permitted to outsource forestry services to private vendors and do so on a regular basis by recommendation from the MFC. This paper finds that the average technical efficiency of the sixteenth section lands is 46%, and there is a positive and statistically significant increase in total timber receipts when a higher proportion of management services are outsourced.Le présent article présente les résultats d'une analyse frontière stochastique de l'efficacité technique de la production de matières ligneuses sur les lots réservés aux écoles publiques dans l'État du Mississippi. Cet État possède deux cents ans d'histoire en gestion de terres publiques destinées au financement des écoles publiques. Les conseils scolaires locaux sont devenus les administrateurs des lots numéro 16 dans les années 1970 et gèrent depuis des augmentations substantielles de revenus tirés de la forêt. La majorité des services de gestion des matières ligneuses sont confiés à la Mississippi Forestry Commission (MFC), agence d'État chargée, entre autres, de la gestion de la matière ligneuse des lots numéro 16. Les arrondissements scolaires et la MFC sont légalement tenus de maximiser les revenus de ces lots. Les arrondissements scolaires peuvent, en vertu de la loi, confier les services forestiers à des entreprises privées, ce qu'ils font régulièrement sur recommandation de la MFC. Les résultats du présent article ont montré une efficacité technique moyenne des lots numéro 16 de 46% et une augmentation statistiquement significative et positive des revenus totaux tirés de la forêt lorsqu'une grande partie des services de gestion étaient impartis.
Landscape Clubs: Co‐existence of Genetically Modified and Organic Crops
Authors: Furtan W. H. , Güzel A. , Weseen A. S. 
Published: May 2007

The possibility of increased production of genetically modified (GM) crops in agriculture accentuates the need to examine the feasibility of GM and non‐GM technologies co‐existing on a common physical landscape. Using the theory of clubs, this paper examines the possibility of co‐existence for GM and organic wheat technologies through the formation of an organic club with an endogenously determined buffer zone. Given the available data on prices, and yields, it is shown that a club can be created in which GM and organic agricultural production technologies can economically co‐exist in the same physical landscape. Specifically, co‐existence results in an increase in economic welfare over a situation where only GM technology is used but is not Pareto superior because producers in the buffer zone will incur injury. We show that organic producers in the club can compensate producers in the buffer zone and still be better off. Hence, the compensation principle holds. La possibilité de production accrue de cultures génétiquement modifiées (GM) accentue la nécessité d'examiner la faisabilité de coexistence des technologies GM et non GM dans un même paysage agricole. À l'aide de la théorie des clubs, le présent article a examiné la possibilité de coexistence des technologies de culture de blé GM et de blé biologique en créant un club ≪biologique≫ comprenant une zone tampon déterminée de façon endogène. Compte tenu des données disponibles concernant les prix et les rendements, il est montré qu'il est possible de créer un club au sein duquel les technologies de production de cultures biologiques et GM peuvent économiquement coexister dans un même paysage naturel. Spécifiquement, la coexistence engendre une augmentation du bien‐être économique par rapport à une situation où seule la technologie GM est utilisée, mais elle n'est pas Pareto supérieure parce que les producteurs dans la zone tampon subiront des dommages. Nous montrons que les producteurs de cultures biologiques membres du club peuvent indemniser les producteurs de la zone tampon tout en demeurant en bonne position. Le principe de compensation tient donc.
Integration to Fragmentation: Post‐BSE Canadian Cattle Markets, Processing Capacity, and Cattle Prices
Authors: Rude James , Carlberg Jared , Pellow Scott 
Published: May 2007

This paper examines the potential impacts of expansions to Canadian cattle slaughter capacity with varying assumptions about the ability to export live cattle to the United States. A synthetic model is calibrated to historic data and then used to gauge the impacts of changing slaughter capacity, commercial grade beef import competition, and export potential for lower quality cuts on the Canadian cattle and beef sector. Expanded slaughter capacity improves fed cattle prices, but cull prices remain below pre‐BSE levels. Reduced ability to export lower quality beef and increased import competition from commercial grade beef also further depress cattle prices. Le présent article examine les répercussions potentielles d'une augmentation de la capacité d'abattage au Canada à l'aide de diverses hypothèses sur la capacité d'exporter des bovins vivants aux États‐Unis. Un modèle synthétique est calibré selon les données historiques et utilisé pour évaluer les répercussions qu'une modification de la capacité d'abattage, de la concurrence quant à l'importation de bœuf de qualité commerciale et de l'exportation éventuelle de coupes de viande de qualité inférieure aurait sur le secteur canadien du bœuf. Une capacité d'abattage accrue améliore les prix des bovins finis, mais les prix des animaux de réforme demeurent inférieurs aux niveaux de prix observés avant la découverte de l'ESB. La diminution de la capacité d'exporter du bœuf de qualité inférieure et l'augmentation de la concurrence pour l'importation de bœuf de qualité commerciale contribuent également à faire baisser davantage les prix des bovins.
A Little Knowledge…: Household Water Quality Investment in the Annapolis Valley
Authors: Janmaat John 
Published: May 2007

A household drinking water and sewage management survey in Nova Scotia's Annapolis Valley suggests that ability to interpret water quality information (proxied by education) strongly affects behavior. Higher education reduces the likelihood of households treating drinking water, but may increase the amount of water treated by households choosing to do so. Septic maintenance may impact water quality, but evidence for jointness in treatment and maintenance choice is absent. Further, increased education weakly reduces septic maintenance. Results suggest that more information about septic source threats to drinking water may induce households to choose more water treatment and less septic maintenance. Information campaigns alone are therefore unlikely to significantly reduce septic source pollution. Une enquête sur la gestion de l'eau potable et des eaux usées menée auprès des ménages de la vallée d'Annapolis en Nouvelle‐Écosse autorise à penser que la capacité d'interpréter l'information sur la qualité de l'eau (déterminée par la variable ≪éducation≫) influence fortement le comportement. Le fait de posséder une éducation supérieure diminue la probabilité que des ménages à traiter l'eau potable, mais peut augmenter la quantité d'eau traitée par ceux qui choisissent de le faire. L'entretien des fosses septiques peut avoir un impact sur la qualité de l'eau, mais il n'existe pas de preuve sur le choix combiné de traiter et d'entretenir. De plus, un niveau d'éducation élevé diminue faiblement le choix d'entretenir les fosses septiques. Les résultats laissent supposer que davantage d'information sur les menaces que représentent les eaux usées pour l'eau potable peut persuader les ménages à choisir davantage de traiter l'eau et à moins entretenir les fosses septiques. Il est donc peu probable que les campagnes d'information seules réussissent à faire diminuer considérablement la pollution provenant des fosses septiques.
On the evolution of the Fe abundance and of the Type Ia supernova rate in clusters of galaxies
Authors: Calura F. , Matteucci F. , Tozzi P. 
Published: May 2007

Abstract
The study of the Fe abundance in the intracluster medium (ICM) provides strong constraints on the integrated star formation history and supernova rate of the cluster galaxies, as well as on the ICM enrichment mechanisms. In this Letter, using chemical evolution models for galaxies of different morphological types, we study the evolution of the Fe content of clusters of galaxies. We assume that the ICM Fe enrichment occurs by means of galactic winds arising from elliptical galaxies and from gas stripped from the progenitors of S0 galaxies via external mechanisms, due to the interaction of the interstellar medium with the ICM. The Fe-rich gas ejected by ellipticals accounts for the XFe,ICM values observed at z &gt; 0.5, whereas the gas stripped from the progenitors of the S0 galaxies accounts for the increase of XFe,ICM observed at z &lt; 0.5. We test two different scenarios for Type Ia supernova (SN) progenitors and we model the Type Ia SN rate observed in clusters, finding a good agreement between our predictions and the available observations.
The present day mass function in the central region of the Arches cluster
Authors: Portegies Zwart Simon , Gaburov Evghenii , Chen Hui-Chen , Gürkan M. Atakan 
Published: May 2007

Abstract
We study the evolution of the mass function in young and dense star clusters by means of direct N-body simulations. Our main aim is to explain the recent observations of the relatively flat mass function observed near the centre of the Arches star cluster. In this region, the power-law index of the mass function for stars more massive than about 5–6 M⊙ is larger than the Salpeter value by about unity, whereas further out, and for the lower mass stars, the mass function resembles the Salpeter distribution. We show that the peculiarities in the Arches mass function can be explained satisfactorily without primordial mass segregation. We draw two conclusions from our simulations: (i) the Arches initial mass function is consistent with a Salpeter slope down to ∼1 M⊙, and (ii) the cluster is about half-way towards core collapse. The cores of other star clusters with characteristics similar to those of the Arches are expected to show similar flattening in the mass functions for the high-mass (≳5 M⊙) stars.
Trends in Ground Water Nitrate Contamination in the Phoenix, Arizona Region
Authors: Xu Ying , Baker Lawrence A. , Johnson Paul C. 
Published: May 2007

AbstractA 60‐year database of nitrate concentrations from more than 200 wells in and around Phoenix, Arizona, was studied using geographic information system tools. This information, augmented with land‐use maps, ground water levels, and well construction details, was used to examine ground water nitrate concentrations and changes in concentration and their relationship to land use, land‐use changes, and changes in hydrologic conditions (as indicated by ground water level changes). Spatially integrated data for the 1960s to 1990s time period suggest slow and subtle temporal changes in the nitrate mass and overall average nitrate concentration in the aquifer, with increases associated with increased nitrogen fertilizer application rates. More recently, declines in nitrate concentration have been observed, which are thought to reflect the combination of declining ground water levels and transitions from agricultural to urban land use in many areas. Temporal trends in ground water nitrate concentration are presented for wells under desert, agricultural, and urban land use and desert‐to‐agriculture, desert‐to‐urban, and agriculture‐to‐urban land‐use change scenarios.
A New Depth‐Discrete Multilevel Monitoring Approach for Fractured Rock
Authors: Cherry John A. , Parker Beth L. , Keller Carl 
Published: May 2007

AbstractA new approach for monitoring in fractured rock was demonstrated in a contaminated (trichloroethylene and metolachlor) dolostone aquifer used for municipal water supply. The system consists of two related technologies: a continuous packer for temporary borehole seals (Flexible Liner Underground Technologies Ltd. [FLUTe] blank liner) and a depth‐discrete multilevel monitoring system (MLS) (the Water FLUTe) for temporary or permanent monitoring. The continuous borehole liner consists of a urethane‐coated nylon fabric tube custom sized to each hole. The FLUTe MLS consists of the same liner material with many depth‐discrete intervals for monitoring hydraulic head and/or ground water quality. The FLUTe blank liner seals the entire borehole, prior to FLUTe multilevel installation, to prevent vertical cross connection while allowing borehole logging and testing. The FLUTe multilevel system also seals the entire borehole with the exception of each monitoring interval where the formation water has direct hydraulic connection to the pumping system via a thin permeable mesh sandwiched between the liner and the formation. The blank sealing liners and the multilevel systems were used in five boreholes ranging in diameter between 9.6 and 14.5 cm in the dolostone aquifer to depths of 150 m. The systems were custom designed for each borehole and included between 12 and 15 monitoring intervals. The application demonstrated the ease of installation and removability and facilitated obtaining large data sets with minimal labor. The system offers unique and versatile design features not possible with other bedrock monitoring devices and has been used at many bedrock contamination sites across North America.
Chemical and Bacterial Quality of Aeration‐Type Waste Water Treatment System Discharge
Authors: Panno Samuel V , Kelly W.R. , Hackley K.C. , Weibel C.P. 
Published: May 2007

AbstractOn‐site waste water treatment systems are a potential source of chemical and bacterial contamination to ground water in areas with highly susceptible aquifers such as the sinkhole plain of southwestern Illinois. Ground water from wells, cave streams, and water that discharges from the numerous springs in this area is typically contaminated with nitrate and enteric bacteria and thus may pose a health hazard to those who come into contact with it. In order to determine if the most popular type of on‐site waste water treatment systems in the study area was a potential source, samples of effluents discharged at the land surface from 23 domestic aeration‐type on‐site waste water treatment systems were collected to characterize their water quality and bacterial contents. Most of the effluents contained relatively large concentrations of sodium (Na+), chloride (Cl−), nutrients (nitrogen [N], phosphate [PO43−], and potassium [K+]), and enteric bacteria. Ion concentration ranges (in mg/L) were Na+ (46 to 416), Cl− (21 to 618), N (4.7 to 67), PO4‐P (1.4 to 48), and K+ (6.0 to 257). The sources of elevated Na+ and Cl− were human waste and NaCl used in the water softening systems of the houses. Ammonium was usually the dominant inorganic N species, indicating incomplete oxidation of the waste water. Discharge of Na+, Cl−, and nutrients could also have negative impacts on ground water and surface water quality, subsurface and surface aquatic ecosystems, and vegetation. Our characterization of effluent from these waste water treatment systems revealed their generally poor quality and the likelihood that they can contaminate ground water in areas with highly vulnerable aquifers.
Electrical Monitoring of In Situ Chemical Oxidation by Permanganate
Authors: Cavé Lisa , Hartog Niels , Al Tom , Parker Beth , Mayer K. Ulrich , Cogswell Steven 
Published: May 2007

AbstractAn array of electrical monitoring probes was constructed to monitor a concentrated permanganate (MnO4−) solution injected to treat perchloroethylene (PCE) contamination in a shallow sandy aquifer. The simple probes use pairs of stainless steel wires as electrodes for electrical conductivity (EC) and platinum wires as the working electrodes for oxidation‐reduction potential (ORP) measurements. Combined EC/ORP probes were assembled into bundles with multilevel ground water samplers and installed in boreholes around the injection point. Copper/copper sulfate half‐cells, inserted to the depth of the water table, acted as ORP reference electrodes. All electrodes were connected to a central data acquisition system, which collected data for a period of 25 d following the injection. Large contrasts in the EC and ORP characteristics of the ground water, compared with the MnO4− solution, allow the subsurface migration of MnO4− to be tracked using these relatively simple electrical measurements. The electrical data were used to track the arrival times of the MnO4− at discrete positions in the aquifer, to guide the timing and selection of locations for water sampling, and for three‐dimensional visualization of the MnO4− distribution during destruction of PCE.
Controls on Spatial Variability of Uranium in Sandstone Aquifers
Authors: Sherman Heidi M. , Gierke John S. , Anderson Cecilia P. 
Published: May 2007

AbstractControls on the spatial variability of uranium (U) in sandstone aquifers were investigated by water sampling and geophysical logging of wells in the Jacobsville Sandstone in Michigan’s Upper Peninsula. 235U/238U isotope ratios in well water are consistent with naturally occurring U, likely derived from U‐enriched strata, which make wells in oxidized, alkaline aquifers at risk for supplying water with elevated U concentrations. Twenty‐nine percent of 218 wells completed in the Jacobsville Sandstone have U concentrations above the U.S. Environmental Protection Agency’s maximum contaminant level (MCL), which is 30 μg/L. Although no regional trends are apparent, neighboring wells tend to have similar U concentrations, except where topography results in significant differences in well bottom elevations. Selected water wells in the Jacobsville Sandstone were logged with a gamma ray spectrometer to determine whether the spatial variability of ground water U concentrations correlates with the distribution of U in the sandstone. Not all wells with relative U enrichment in the sandstone produce water with U above the MCL, indicating that the influence of U enrichment in aquifer material may be modified by other hydrogeochemical factors. Ground water age dating may help explain variations in well water U concentrations by identifying water‐leaching U for varying periods of time. These results may have implications for interpreting controls on the spatial variability of naturally occurring contaminants in ground water in other areas. This study supports the general utility of U isotope data to investigate rock water interactions.
Heuristic Approach for Renovating a Monitoring Network Measuring Sea Water Intrusion into the Coastal Aquifer
Authors: Melloul Abraham J. , Aberbach Shmuel 
Published: May 2007

AbstractCoastal aquifer management requires rapid and effective decision making as regards rapid ground water salinity and volume changes. This can be assessed only by means of an efficient sea water monitoring network that can lead to a more exact location of sea water intrusion and the ground water quality trends of the area of study and a hydrogeologist who understands the mechanism of the aquifer. This article proposes a “heuristic” approach for prioritizing aquifer areas for improving the monitoring network by adding new observation wells and renovating old ones. Such an approach improves aquifer control by recommending where additional and renovation observation wells are required regarding sea water intrusion along coastal aquifers. The data in use for this approach consist of variables characterizing the hydrological situation in the aquifer and the technical conditions of sea water intrusion network observation wells within their ground water salinity environment. Applied to Israel’s coastal aquifer, this approach leads to a list of areas with highest priorities, most of which are located in the northern portion of the Coastal Plain aquifer. Such a list is a basis document for decision making, which helps focus upon areas where it is most urgent to improve the quality of information by drilling new observation wells or by rehabilitation of the technical conditions of the present sea water intrusion observation well network. Considering the results obtained, this approach may be considered as a means for requiring further input data for various hydrological models and for operational activities in the field.