TRADEOFF BETWEEN ECONOMIES OF SIZE IN TREATMENT AND DISECONOMIES OF DISTRIBUTION FOR RURAL WATER SYSTEMS

This paper outlines a method to determine the tradeoff between economies of size in water treatment and diseconomies of distribution. Cost equations are estimated for several treatment technologies and distribution extensions. Empirical results are used to identify optimal system size where average total costs are minimized. Regardless of treatment, most costs are due to distribution. As water systems expand service territories, only in the most densely populated areas would remaining economies of size in treatment outweigh the diseconomies in distribution.Resource /Energy Economics and Policy,

\u3cem\u3eEx Vivo\u3c/em\u3e Diffusion Tensor Imaging of Spinal Cord Injury in Rats of Varying Degrees of Severity

The aim of this study was to characterize magnetic resonance diffusion tensor imaging (DTI) in proximal regions of the spinal cord following a thoracic spinal cord injury (SCI). Sprague–Dawley rats (n = 40) were administered a control, mild, moderate, or severe contusion injury at the T8 vertebral level. Six direction diffusion weighted images (DWIs) were collected ex vivo along the length of the spinal cord, with an echo/repetition time of 31.6 ms/14 sec and b = 500 sec/mm2. Diffusion metrics were correlated to hindlimb motor function. Significant differences were found for whole cord region of interest (ROI) drawings for fractional anisotropy (FA), mean diffusivity (MD), longitudinal diffusion coefficient (LD), and radial diffusion coefficient (RD) at each of the cervical levels ( p \u3c 0.01). Motor function correlated with MD in the cervical segments of the spinal cord (r2 = 0.80). The diffusivity of water significantly decreased throughout ‘‘uninjured’’ portions of the spinal cord following a contusion injury ( p \u3c 0.05). Diffusivity metrics were found to be altered following SCI in both white and gray matter regions. Injury severity was associated with diffusion changes over the entire length of the cord. This study demonstrates that DTI is sensitive to SCI in regions remote from injury, suggesting that the diffusion metrics may be used as a biomarker for severity of injury

A HEDONIC APPROACH TO ESTIMATING OPERATION AND MAINTENANCE COSTS FOR NEW YORK MUNICIPAL WATER SYSTEMS

A hedonic cost function is used to isolate the operation and maintenance costs for water treatments. For small systems, costs are substantial for some technologies, but not for others. When regional differences in input costs are accounted for, small systems located in rural areas may have a cost advantage over similar systems closer to urban centers; however, costs of water treatment to meet Safe Drinking Water Act amendments may still be substantial.Public Economics,

NY Pollution Discharge Elimination Permits for CAFOs, Management Adjustments and the Environment

Weakening demand for livestock and dairy produce, historically high prices for feed ingredients and increasingly strict regulations on animal waste management continue to put significant pressure on livestock and dairy operating margins. In this paper, we use representative farm mathematical programming models to analyze important linkages between farm management adjustments and changes in farm income due to recent changes in relevant agricultural prices and restrictions on land application of nutrients. We account explicitly for new restrictions on land application of nitrogen and phosphorus, and specifically applied to confined animal feeding operations (CAFOs). Our mathematical methods and the distinctive data available allows for the assessment of the effects on income and environmental nutrient loading for New York State dairy production farms. The results suggest that with current relative prices for feed ingredients, adjustments to dairy rations lead to increased nitrogen and phosphorus content in dairy waste and soil nutrient levels being applied well in excess of crop requirements. While the regulations will correct for this problem at the farm level, our results indicate that CAFOs could experience significant losses in income. These losses depend critically on the cost of off-site manure disposal. Our results also demonstrate that significant risks of excess nutrient loading remain during extreme weather events.CAFO regulations, nutrient management, manure disposal, mathematical programming, environmental quality, Environmental Economics and Policy, Farm Management, Production Economics,

Diffusion Imaging in the Rat Cervical Spinal Cord

Magnetic resonance imaging (MRI) is the state of the art approach for assessing the status of the spinal cord noninvasively, and can be used as a diagnostic and prognostic tool in cases of disease or injury. Diffusion weighted imaging (DWI), is sensitive to the thermal motion of water molecules and allows for inferences of tissue microstructure. This report describes a protocol to acquire and analyze DWI of the rat cervical spinal cord on a small-bore animal system. It demonstrates an imaging setup for the live anesthetized animal and recommends a DWI acquisition protocol for high-quality imaging, which includes stabilization of the cord and control of respiratory motion. Measurements with diffusion weighting along different directions and magnitudes (b-values) are used. Finally, several mathematical models of the resulting signal are used to derive maps of the diffusion processes within the spinal cord tissue that provide insight into the normal cord and can be used to monitor injury or disease processes noninvasively. The video component of this article can be found at http://www.jove.com/video/52390/ Introduction Magneti

Clinical Correlates of High Cervical Fractional Anisotropy in Acute Cervical Spinal Cord Injury

Objective: Fractional anisotropy (FA) of the high cervical cord (C1-C2), rostral to the injury site, correlates with upper limb function in patients with chronic cervical spinal cord injury (SCI). In acute cervical SCI, this relationship has not been investigated. The objective of this study was to identify functional correlates of FA of the high cervical cord in a series of patients with acute cervical SCI. Methods: Traumatic cervical SCI patients who underwent presurgical cervical spine diffusion tensor imaging at our institution were reviewed for this study. FA of the whole cord as well as the lateralcorticospinal tracts (CSTs) was calculated on axial images from C1-C2. Upper limb motor (C5-T1) and sensory (C2-T1) function scores were extracted from the admission American Spinal Injury Association (ASIA) examinations. Correlation analysis for FA with ASIA examinations was performed using a Pearson correlation. Results: Twelve subjects (9 men, 3 women; mean age 54.7 ± 4.0 years) underwent cervical spine diffusion tensor imaging at a mean duration of 3.6 ± 0.9 days postinjury. No patient had cord compression or intramedullary T2-weighted hyperintensities within the C1-C2 segments. FA correlated with upper limb motor score (whole cord: r = 0.59, P = .04; CST: 0.67, P = .01) and the ASIA grade (whole cord: r = 0.61, P = .03; CST: r = 0.71, P = .009). No correlation was found between FA and sensory scores. Conclusions: FA of the whole cervical cord as well as the CST, rostral to the injury site, is associated with preserved upper limb motor function as well as superior ASIA grades after acute cervical SCI. FA of the high cervical cord is a potential biomarker of neural injury after acute cervical SCI

Dairy Farm Management Adjustments to Biofuels-Induced Changes in Agricultural Markets

A mathematical programming model of a representative New York dairy farm is developed to identify optimal management adjustments to increased availability of corn distillers dried grains with solubles (DDGS). While at current prices DDGS feeding is limited to dry cows and young stock, as prices decrease, DDGS in lactating cow rations increase from 7.4% to 20% on a dry matter basis. While expected changes in net farm returns are modest, more important is the consideration of changes in nutrient management practices necessary to deal with increasing levels of nitrogen and phosphorus in the animal waste.Production, Management, Agribusiness, Agricultural Finance, Farm Management, Financial Economics, Resource /Energy Economics and Policy,

Evaluating Marketing Channel Options for Small-Scale Fruit and Vegetable Producers

An investigation of the relative costs and benefits of marketing channels used by typical smallscale diversified vegetable crop producers is conducted. Using case study evidence from four small farms in Central New York, this study compares the performance of wholesale and direct marketing channels, including how the factors of risk, owner and paid labor, price, lifestyle preferences, and sales volume interact to impact optimal market channel selection. Given the highly perishable nature of the crops grown, along with the risks and potential sales volume of particular channels, a combination of different marketing channels is needed to maximize overall firm performance. Accordingly, a ranking system is developed to summarize the major firm-specific factors across channels and to prioritize those channels with the greatest opportunity for success based on individual firm preferences.local food, marketing, wholesale, direct, marketing channels, economic evaluation, Agribusiness, Community/Rural/Urban Development, Crop Production/Industries, Demand and Price Analysis, Production Economics,

Evaluating Marketing Channel Options for Small-Scale Fruit and Vegetable Producers: Case Study Evidence from Central New York

An investigation of the relative costs and benefits of marketing channels used by typical small-scale diversified vegetable crop producers is conducted. Using case study evidence from four small farms in Central New York, this study compares the performance of wholesale and direct marketing channels, including how the factors of risk, owner and paid labor, price, lifestyle preferences, and sales volume interact to impact optimal market channel selection. Given the highly perishable nature of the crops grown, along with the risks and potential sales volume of particular channels, a combination of different marketing channels is needed to maximize overall firm performance. Accordingly, a ranking system is developed to summarize the major firm-specific factors across channels and to prioritize those channels with the greatest opportunity for success based on individual firm preferences.Marketing channel, small-scale, fruit and vegetable producers, case study, Agribusiness, Crop Production/Industries, Financial Economics,

Economies of Size in Water Treatment vs. Diseconomies of Dispersion for Small Public Water Systems

WP 1996-15 November 1996This paper outlines a method to determine the tradeoff between economies of size in water treatment and diseconomies of distribution. Empirical results for New York are used to identify the implications for the rehabilitation and consolidation of rural water systems