1,419 research outputs found
What Drives Land-Use Change in the United States? A National Analysis of Landowner Decisions
Land-use changes involve important economic and environmental effects with implications for international trade, global climate change, wildlife, and other policy issues. We use an econometric model to identify factors driving land-use change in the United States between 1982 and 1997. We quantify the effects of net returns to alternative land uses on private landowners’ decisions to allocate land among six major uses, drawing on detailed micro-data on land use and land quality that are comprehensive of the contiguous U.S. This analysis provides the first evidence of the relative historical importance of markets and Federal farm policies affecting land-use changes nationally.Land Use, Land-Use Change, Econometric Analysis, Simulations
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Nilotinib, an approved leukemia drug, inhibits smoothened signaling in Hedgehog-dependent medulloblastoma.
Dysregulation of the seven-transmembrane (7TM) receptor Smoothened (SMO) and other components of the Hedgehog (Hh) signaling pathway contributes to the development of cancers including basal cell carcinoma (BCC) and medulloblastoma (MB). However, SMO-specific antagonists produced mixed results in clinical trials, marked by limited efficacy and high rate of acquired resistance in tumors. Here we discovered that Nilotinib, an approved inhibitor of several kinases, possesses an anti-Hh activity, at clinically achievable concentrations, due to direct binding to SMO and inhibition of SMO signaling. Nilotinib was more efficacious than the SMO-specific antagonist Vismodegib in inhibiting growth of two Hh-dependent MB cell lines. It also reduced tumor growth in subcutaneous MB mouse xenograft model. These results indicate that in addition to its known activity against several tyrosine-kinase-mediated proliferative pathways, Nilotinib is a direct inhibitor of the Hh pathway. The newly discovered extension of Nilotinib's target profile holds promise for the treatment of Hh-dependent cancers
Land-Use Change and Carbon Sinks: Econometric Estimation of the Carbon Sequestration Supply Function
When and if the United States chooses to implement a greenhouse gas reduction program, it will be necessary to decide whether carbon sequestration policies, such as those that promote forestation and discourage deforestation, should be part of the domestic portfolio of compliance activities. We investigate the cost of forest-based carbon sequestration. In contrast with previous approaches, we econometrically examine micro-data on revealed landowner preferences, modeling six major private land uses in a comprehensive analysis of the contiguous United States. The econometric estimates are used to simulate landowner responses to sequestration policies. Key commodity prices are treated as endogenous and a carbon sink model is used to predict changes in carbon storage. Our estimated marginal costs of carbon sequestration are greater than those from previous engineering cost analyses and sectoral optimization models. Our estimated sequestration supply function is similar to the carbon abatement supply function from energy-based analyses, suggesting that forest-based carbon sequestration merits inclusion in a cost-effective portfolio of domestic U.S. climate change strategies.Environment, Regulatory Reform
Senator James O. Eastland, Bob Dole, Milton R. Young, Carl T. Curtis, George McGovern, James B. Allen, and Hubert H. Humphrey to President Jimmy Carter, 30 September 1977
Copy typed letter signed dated 30 September 1977 from Eastland, Bob Dole, Milton R. Young, Carl T. Curtis, George McGovern, James B. Allen, and Hubert H. Humphrey to Carter, re: sugar tariffs, S. 275 (Food and Agriculture Act of 1977); 2 pages.https://egrove.olemiss.edu/joecorr_h/1064/thumbnail.jp
Mannose binding lectin is required for alphavirus-induced arthritis/myositis
Mosquito-borne alphaviruses such as chikungunya virus and Ross River virus (RRV) are emerging pathogens capable of causing large-scale epidemics of virus-induced arthritis and myositis. The pathology of RRV-induced disease in both humans and mice is associated with induction of the host inflammatory response within the muscle and joints, and prior studies have demonstrated that the host complement system contributes to development of disease. In this study, we have used a mouse model of RRV-induced disease to identify and characterize which complement activation pathways mediate disease progression after infection, and we have identified the mannose binding lectin (MBL) pathway, but not the classical or alternative complement activation pathways, as essential for development of RRV-induced disease. MBL deposition was enhanced in RRV infected muscle tissue from wild type mice and RRV infected MBL deficient mice exhibited reduced disease, tissue damage, and complement deposition compared to wild-type mice. In contrast, mice deficient for key components of the classical or alternative complement activation pathways still developed severe RRV-induced disease. Further characterization of MBL deficient mice demonstrated that similar to C3(-/-) mice, viral replication and inflammatory cell recruitment were equivalent to wild type animals, suggesting that RRV-mediated induction of complement dependent immune pathology is largely MBL dependent. Consistent with these findings, human patients diagnosed with RRV disease had elevated serum MBL levels compared to healthy controls, and MBL levels in the serum and synovial fluid correlated with severity of disease. These findings demonstrate a role for MBL in promoting RRV-induced disease in both mice and humans and suggest that the MBL pathway of complement activation may be an effective target for therapeutic intervention for humans suffering from RRV-induced arthritis and myositis.This work was supported by NIH/NIAMS R01 AR 047190 awarded to MTH
The Conservation Reserve Program: Economic Implications for Rural America
This report estimates the impact that high levels of enrollment in the Conservation Reserve Program (CRP) have had on economic trends in rural counties since the program's inception in 1985 until today. The results of a growth model and quasi-experimental control group analysis indicate no discernible impact by the CRP on aggregate county population trends. Aggregate employment growth may have slowed in some high-CRP counties, but only temporarily. High levels of CRP enrollment appear to have affected farm-related businesses over the long run, but growth in the number of other nonfarm businesses moderated CRP's impact on total employment. If CRP contracts had ended in 2001, simulation models suggest that roughly 51 percent of CRP land would have returned to crop production, and that spending on outdoor recreation would decrease by as much as $300 million per year in rural areas. The resulting impacts on employment and income vary widely among regions having similar CRP enrollments, depending upon local economic conditions.Community/Rural/Urban Development, Land Economics/Use,
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Land-use change and carbon sinks: Econometric estimation of the carbon sequestration supply function
Increased attention by policy makers to the threat of global climate change has brought with it considerable interest in the possibility of encouraging the expansion of forest area as a means of sequestering carbon dioxide. The marginal costs of carbon sequestration or, equivalently, the carbon sequestration supply function will determine the ultimate effects and desirability of policies aimed at enhancing carbon uptake. In particular, marginal sequestration costs are the critical statistic for identifying a cost-effective policy mix to mitigate net carbon dioxide emissions. We develop a framework for conducting an econometric analysis of land use for the forty-eight contiguous United States and employing it to estimate the carbon sequestration supply function. By estimating the opportunity costs of land on the basis of econometric evidence of landowners' actual behavior, we aim to circumvent many of the shortcomings of previous sequestration cost assessments. By conducting the first nationwide econometric estimation of sequestration costs, endogenizing prices for land-based commodities, and estimating land-use transition probabilities in a framework that explicitly considers the range of land-use alternatives, we hope to provide better estimates eventually of the true costs of large-scale carbon sequestration efforts. In this way, we seek to add to understanding of the costs and potential of this strategy for addressing the threat of global climate change
Decade-long trends (1999-2009) in the characteristics, management, and hospital outcomes of patients hospitalized with acute myocardial infarction with prior diabetes and chronic kidney disease
BACKGROUND: Despite the increasing magnitude and impact, there are limited data available on the clinical management and in-hospital outcomes of patients who have diabetes mellitus (DM) and chronic kidney disease (CKD) at the time of hospitalization for acute myocardial infarction (AMI). The objectives of our population-based observational study in residents of central Massachusetts were to describe decade-long trends (1999-2009) in the characteristics, in-hospital management, and hospital outcomes of AMI patients with and without these comorbidities.
METHODS: We reviewed the medical records of 6,018 persons who were hospitalized for AMI on a biennial basis between 1999 and 2009 at all eleven medical centers in central Massachusetts. Our sample consisted of the following four groups: DM with CKD (n=587), CKD without DM (n=524), DM without CKD (n=1,442), and non-DM/non-CKD (n=3,465).
RESULTS: Diabetic patients with CKD were more likely to have a higher prevalence of previously diagnosed comorbidities, to have developed heart failure acutely, and to have a longer hospital stay compared with non-DM/non-CKD patients. Between 1999 and 2009, there were marked increases in the prescribing of beta-blockers, statins, and aspirin for patients with CKD and DM as compared to those without these comorbidities. In-hospital death rates remained unchanged in patients with DM and CKD, while they declined markedly in patients with CKD without DM (20.2% dying in 1999; 11.3% dying in 2009).
CONCLUSION: Despite increases in the prescribing of effective cardiac medications, AMI patients with DM and CKD continue to experience high in-hospital death rates
Functional studies of the kidney of living animals using multicolor 2-photon microscopy
Optical microscopy, when applied to living animals, provides a powerful means of studying cell biology in the most physiologically relevant setting. The ability of two-photon microscopy to collect optical sections deep into biological tissues has opened up the field of intravital microscopy to high-resolution studies of the brain, lens, skin, and tumors. Here we present examples of the way in which two-photon microscopy can be applied to intravital studies of kidney physiology. Because the kidney is easily externalized without compromising its function, microscopy can be used to evaluate various aspects of renal function in vivo. These include cell vitality and apoptosis, fluid transport, receptor-mediated endocytosis, blood flow, and leukocyte trafficking. Efficient two-photon excitation of multiple fluorophores permits comparison of multiple probes and simultaneous characterization of multiple parameters and yields spectral information that is crucial to the interpretation of images containing uncharacterized autofluorescence. The studies described here demonstrate the way in which two-photon microscopy can provide a level of resolution previously unattainable in intravital microscopy, enabling kinetic analyses and physiological studies of the organs of living animals with subcellular resolution
Ex vivo Evaluation of a New Drill System for Placement of Percutaneous Bone Conduction Devices
The procedure for installation of a percutaneous bone-conducting device has undergone significant improvements since its introduction 40 years ago. Today, the linear incision technique with tissue preservation (LITT-P) and the minimally invasive procedure (MIPS) are the most commonly used approaches. In both these techniques, a gradual increase of the osteotomy using a three-step drilling sequence is utilized, as this approach can allow a stepwise deepening and widening of the osteotomy in the mastoid and can prevent bone overheating. A new minimally invasive procedure (MONO) has been developed that allows an osteotomy to be performed and enables complete removal of the bone volume in one single drill step for a 4 mm implant using a novel parabolic twist drill. Here, the feasibility of the MONO procedure was qualitatively and quantitatively evaluated in terms of the dura response to drill trauma in comparison with the outcomes achieved with guide drills used for the LITT-P and MIPS techniques. Fresh frozen temporal bone from a human cadaver was subjected to penetration by three drills beyond the base of the mastoid bone to different depths. The sites were evaluated, and the damage to and possible penetration of the dura were determined. The results showed that for a drill depth exceeding mastoid bone thickness by not more than 1 mm, damage to the dura was limited or nonexistent, whereas for a drill depth exceeding bone thickness by 2 mm, damage increased, or the dura was penetrated. There was a trend toward more damage and penetration for both the round burr and MIPS guide drill compared with the MONO drill bit. From this experimental ex vivo study, it can be concluded that if the dura is encountered, the MONO system is not more inclined to penetrate the dura than the conventional LITT-P and MIPS systems
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