1,508 research outputs found

    The Effects of Available Water Upon Populations of Chukar Partridge on Desert Mountains of Utah

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    The importance of surface water to chukar partridges (Alectoris graeca) and the feasibility of rain-catchment devices for improving chukar habitat were studied on the Thomas and Dugway Mountain Ranges in western Utah during 1969 and 1970. Sources of surface water were removed from one mountain rang~ and chukar populations on that range were compared with populations on an adjacent range with permanent sources of water. Providing drinking water did not improve chukar productivity, survival, or availability to hunters. Although most birds concentrated around water supplies in the summer, some chukars appeared to live completely independent of any permanent sources of surface water. Food habits of chukars near water did not differ from those in waterless areas. It was concluded that in habitats comparable to those studied, installation of rain-catchment devices is not a feasible technique for improving chukar habitat

    The Productivity of Pharmaceuticals in Improving Health: An Analysis of the OECD Health Data

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    Although a number of studies have been conducted on health production functions, little attention has been given to pharmaceuticals as a separate input into the production of health. Building upon existing published work, this paper uses an alternative specification and more recent data to estimate the effect of pharmaceutical expenditures on levels of health in the member countries of the Organization for Economic Cooperation and Development (OECD). In a sample of developed countries, we found that pharmaceutical consumption, as measured by per capita drug expenditures, has a positive effect on life expectancy at advanced ages. The marginal effect of pharmaceutical consumption is consistent with estimates that have been reported previously but appears to decline with increasing age. Over the past few years, the substantial and disproportionate growth of pharmaceutical expenditures for public and private payers in the U.S. has led to calls for regulatory intervention (e.g., price controls). However, our research suggests that increases in drug spending may yield further increases in life expectancy.Health production, life expectancy, pharmaceuticals, OECD, ecological studies

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    Climate Change Challenges for Land Conservation: Rethinking Conservation Easements, Strategies, and Tools

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    Climate change has significant consequences for land conservation. Government agencies and nonprofit land trusts heavily rely on perpetual conservation easements. However, climate change and other dynamic landscape changes raise questions about the effectiveness and adaptability of permanent conservation instruments like conservation easements. Building upon a study of 269 conservation easements and interviews with seventy conservation-easement professionals in six different states, we examine the adaptability of conservation easements to climate change. We outline four potential approaches to enhance conservation outcomes under climate change: (1) shift land-acquisition priorities to account for potential climate-change impacts; (2) consider conservation tools other than perpetual conservation easements; (3) ensure that the terms of conservation easements permit the holder to adapt to climate change successfully; and (4) provide for more active stewardship of conservation lands. There is still a good deal of uncertainty as to the legal fate of a conservation easement that no longer meets its original purposes. Many state laws provide that conservation easements can be modified or terminated in the same manner as traditional easements. Yet, conservation easements are in many ways unlike other easements. The beneficiary is usually the public, not merely a neighboring landowner, and the holder is always a non-profit conservation organization or a government agency. Thus, there is a case to be made for adaptive protection. An overly narrow focus on perpetual property rights could actually thwart efforts to meet adaptation needs over the long term. We call for careful attention to ensuring conservation outcomes in dynamic landscapes over time

    A comparison of three fingerstick, whole blood antibody tests for Helicobacter pylori infection: a United States, multicenter trial

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    We compared three whole blood antibody tests for Helicobacter pylori ( H. pylori ) in a United States, multicenter trial. Methods Patients referred for EGD at three medical centers were recruited. During EGD, biopsies were taken for histology and rapid urease testing (RUT). Immediately after endoscopy, patients underwent the antibody tests (FlexPack HP, Abbott Diagnostics; QuikVue, Quidel Corporation; AccuMeter, ChemTrak) using whole blood obtained by two to three fingersticks. Performance characteristics were calculated for each antibody test using the biopsy-based methods as a gold standard. Results A total of 131 patients participated; 50 (38%) patients had histological evidence of H. pylori infection. Using histology as a gold standard, the sensitivities of FlexPack HP, QuikVue, and Accumeter were 76%, 78%, and 84%, respectively. Specificity was 79% with FlexPack HP and 90% with QuikVue and Accumeter. There were no significant differences in the performance of the three antibody tests though there was a trend toward superior performance for AccuMeter compared to FlexPack HP ( p = 0.019 ). However, RUT proved superior to FlexPack HP using histology as a gold standard ( p = 0.008 ). Using either concordant histology and RUT results or a positive histology or RUT to define active H. pylori infection, there was no statistically significant difference between the antibody tests. Conclusions There were no statistically significant differences in the performance of the three antibody tests. These tests proved only marginally sensitive in detecting patients infected with H. pylori . Clinicians should be aware of the limitations of these tests, particularly when using them as a sole means of testing for H. pylori .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72148/1/j.1572-0241.1999.1135_x.x.pd

    Climate Change Challenges for Land Conservation: Rethinking Conservation Easements, Strategies, and Tools

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    Climate change has significant consequences for land conservation. Government agencies and nonprofit land trusts heavily rely on perpetual conservation easements. However, climate change and other dynamic landscape changes raise questions about the effectiveness and adaptability of permanent conservation instruments like conservation easements. Building upon a study of 269 conservation easements and interviews with seventy conservation-easement professionals in six different states, we examine the adaptability of conservation easements to climate change. We outline four potential approaches to enhance conservation outcomes under climate change: (1) shift land-acquisition priorities to account for potential climate change impacts; (2) consider conservation tools other than perpetual conservation easements; (3) ensure that the terms of conservation easements permit the holder to adapt to climate change successfully; and (4) provide for more active stewardship of conservation lands. There is still a good deal of uncertainty as to the legal fate of a conservation easement that no longer meets its original purposes. Many state laws provide that conservation easements can be modified or terminated in the same manner as traditional easements. Yet conservation easements are in many ways unlike other easements. The beneficiary is usually the public, not merely a neighboring landowner, and the holder is always a nonprofit conservation organization or a government agency. Thus, there is a case to be made for adaptive protection. An overly narrow focus on perpetual property rights could actually thwart efforts to meet adaptation needs over the long term. We call for careful attention to ensuring conservation outcomes in dynamic landscapes over time

    Development of a risk adjustment mortality model using the American College of Cardiology–National Cardiovascular Data Registry (ACC–NCDR) experience: 1998–2000

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    AbstractObjectivesWe sought to develop and evaluate a risk adjustment model for in-hospital mortality following percutaneous coronary intervention (PCI) procedures using data from a large, multi-center registry.BackgroundThe 1998–2000 American College of Cardiology–National Cardiovascular Data Registry (ACC–NCDR) dataset was used to overcome limitations of prior risk-adjustment analyses.MethodsData on 100,253 PCI procedures collected at the ACC–NCDR between January 1, 1998, and September 30, 2000, were analyzed. A training set/test set approach was used. Separate models were developed for presentation with and without acute myocardial infarction (MI) within 24 h.ResultsFactors associated with increased risk of PCI mortality (with odds ratios in parentheses) included cardiogenic shock (8.49), increasing age (2.61 to 11.25), salvage (13.38) urgent (1.78) or emergent PCI (5.75), pre-procedure intra-aortic balloon pump insertion (1.68), decreasing left ventricular ejection fraction (0.87 to 3.93), presentation with acute MI (1.31), diabetes (1.41), renal failure (3.04), chronic lung disease (1.33); treatment approaches including thrombolytic therapy (1.39) and non-stent devices (1.64); and lesion characteristics including left main (2.04), proximal left anterior descending disease (1.97) and Society for Cardiac Angiography and Interventions lesion classification (1.64 to 2.11). Overall, excellent discrimination was achieved (C-index = 0.89) and application of the model to high-risk patient groups demonstrated C-indexes exceeding 0.80. Patient factors were more predictive in the MI model, while lesion and procedural factors were more predictive in the analysis of non-MI patients.ConclusionsA risk adjustment model for in-hospital mortality after PCI was successfully developed using a contemporary multi-center registry. This model is an important tool for valid comparison of in-hospital mortality after PCI

    Multiple frequency EPR studies on three forms of oxidized cytochrome c oxidase

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    Bovine heart mitochondrial cytochrome c oxidase (cytochrome aa3) (EC 1.9.3.1) has been demonstrated to occur in several forms when the redox centers in the protein are thought to be fully oxidized. We report here the results of extensive EPR studies at 3, 8.9, 9.2, 9.4, 15 and 34 GHz on the resting state, the alternative resting state (with g = 12 at 9 GHz) and pulsed state (with g = 5 signal at 9 GHz). Theoretical consideration is given to all binary spin-coupling possibilities under the constraint that the iron atoms are either ferric or ferrous and the copper atoms are either cupric or cuprous. We conclude that the g = 12 signal can arise from any spin system with S > 1 and |D| = 0.15 cm-1. The g = 5 signals originate from an excited, integer-spin system with |D| = 0.035 cm-1, which is approximately 7 cm-1 above the ground state (not observed in EPR). It is pointed out that in interpretations of data and elaboration of suitable models in this field, the implications of spin-coupling should be considered in a comprehensive and not in a selective way. At 3 GHz, EPR spectra of CuA in the resting, pulsed and anaerobically oxidized states show that this center is identical in its EPR for all three states.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25085/1/0000516.pd
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