339 research outputs found

    THE CONTRIBUTION OF ENVIRONMENTAL AMENITIES TO AGRICULTURAL LAND VALUES: HEDONIC MODELLING USING GEOGRAPHIC INFORMATION SYSTEMS DATA

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    Geographic Information Systems (GIS) data are used in a hedonic model to measure the impact of recreational and scenic amenities on agricultural land values. Results indicate agricultural land values are determined by environmental amenities as well as production attributes. Significant amenity variables included scenic view, elk habitat and fishery productivity.Environmental Economics and Policy, Land Economics/Use,

    Montane meadow change during drought varies with background hydrologic regime and plant functional group

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    Climate change models for many ecosystems predict more extreme climatic events in the future, including exacerbated drought conditions. Here we assess the effects of drought by quantifying temporal variation in community composition of a complex montane meadow landscape characterized by a hydrological gradient. The meadows occur in two regions of the Greater Yellowstone Ecosystem (Gallatin and Teton) and were classified into six categories (M1–M6, designating hydric to xeric) based upon Satellite pour l’Observation de la Terre (SPOT) satellite imagery. Both regions have similar plant communities, but patch sizes of meadows are much smaller in the Gallatin region. We measured changes in the percent cover of bare ground and plants by species and functional groups during five years between 1997 and 2007. We hypothesized that drought effects would not be manifested evenly across the hydrological gradient, but rather would be observed as hotspots of change in some areas and minimally evident in others. We also expected varying responses by plant functional groups (forbs vs. woody plants). Forbs, which typically use water from relatively shallow soils compared to woody plants, were expected to decrease in cover in mesic meadows, but increase in hydric meadows. Woody plants, such as Artemisia, were expected to increase, especially in mesic meadows. We identified several important trends in our meadow plant communities during this period of drought: (1) bare ground increased significantly in xeric meadows of both regions (Gallatin M6 and Teton M5) and in mesic (M3) meadows of the Teton, (2) forbs decreased significantly in the mesic and xeric meadows in both regions, (3) forbs increased in hydric (M1) meadows of the Gallatin region, and (4) woody species showed increases in M2 and M5 meadows of the Teton region and in M3 meadows of the Gallatin region. The woody response was dominated by changes in Artemisia spp. and Chrysothamnus viscidiflorus. Thus, our results supported our expectations that community change was not uniform across the landscape, but instead could be predicted based upon functional group responses to the spatial and temporal patterns of water availability, which are largely a function of plant water use and the hydrological gradient.This material is based upon research supported by the National Science Foundation under Grants 0518150 and EPS0814387, the Environmental Protection Agency under STAR Grant R825155, the University of Wyoming National Park Service Research Station, and the Grand Teton Natural History Association. We thank the University of Wyoming National Park Service Research Station (particularly Henry Harlow and Sue Consolo-Murphy) and the U.S. Forest Service for providing support and housing. Philip Dixon provided statistical consulting, and Mark Jakubauskas collaborated in setting up our initial field campaigns. Edward Cook assisted in selection and assessment of PDSI data; and Lisa Graumlich, Andy Bunn, Steve Gray, and Jeremy Littel advised us on climate reconstruction options for the GYE. Scott Creel, Sue Fairbanks, and Matt Kaufmann provided information on elk population trends in the region. Jill Sherwood designed the map. William Clark and two anonomous reviewers provided important suggestions that helped improve the manuscript. Finally, we thank the many research technicians and field assistants who helped in the fieldwork

    Montane Meadow Change during Drought Varies with Background Hydrologic Regime and Plant Functional Group

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    Climate change models for many ecosystems predict more extreme climatic events in the future, including exacerbated drought conditions. Here we assess the effects of drought by quantifying temporal variation in community composition of a complex montane meadow landscape characterized by a hydrological gradient. The meadows occur in two regions of the Greater Yellowstone Ecosystem (Gallatin and Teton) and were classified into six categories (M1–M6, designating hydric to xeric) based upon Satellite pour l’Observation de la Terre (SPOT) satellite imagery. Both regions have similar plant communities, but patch sizes of meadows are much smaller in the Gallatin region. We measured changes in the percent cover of bare ground and plants by species and functional groups during five years between 1997 and 2007. We hypothesized that drought effects would not be manifested evenly across the hydrological gradient, but rather would be observed as hotspots of change in some areas and minimally evident in others. We also expected varying responses by plant functional groups (forbs vs. woody plants). Forbs, which typically use water from relatively shallow soils compared to woody plants, were expected to decrease in cover in mesic meadows, but increase in hydric meadows. Woody plants, such as Artemisia, were expected to increase, especially in mesic meadows. We identified several important trends in our meadow plant communities during this period of drought: (1) bare ground increased significantly in xeric meadows of both regions (Gallatin M6 and Teton M5) and in mesic (M3) meadows of the Teton, (2) forbs decreased significantly in the mesic and xeric meadows in both regions, (3) forbs increased in hydric (M1) meadows of the Gallatin region, and (4) woody species showed increases in M2 and M5 meadows of the Teton region and in M3 meadows of the Gallatin region. The woody response was dominated by changes in Artemisia spp. and Chrysothamnus viscidiflorus. Thus, our results supported our expectations that community change was not uniform across the landscape, but instead could be predicted based upon functional group responses to the spatial and temporal patterns of water availability, which are largely a function of plant water use and the hydrological gradient

    The Attrition of Young Physician-Scientists: Problems and Potential Solutions

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    Physician-scientists have played a prominent role as thought leaders in American medicine over the past century. This group has produced many basic scientific advances and pioneered the translation of these advances into clinical practice. Now that we are in the post-genomic era, there is a greater need than ever for the continued participation of this group because of their unique ability to bridge the "bench to bedside." However, the number of physicians pursuing this career is static and their average age is rising. Recent data indicate that the many benefits of this career path are seen as being outweighed by so many negative factors, as to prompt the question, "Is this a career that a reasonable person should undertake in 2007 and beyond?" The following analysis suggests that the current answer is "no." We have identified the lack of professional security as a major factor that prompts young physicians to abandon the physician-scientist track. Because this problem has not been sufficiently emphasized, we believe current efforts are unlikely to reverse this disturbing trend. We propose strategies that seek to address this problem and help sustain young physician-scientists at career transition points at which they are most vulnerable to give up

    Integration of Weed-Suppressive Bacteria with Herbicides to Reduce Exotic Annual Grasses and Wildfire Problems on ITD Right-of-Ways

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    Invasion by exotic-annual grasses such as cheatgrass is impacting semiarid rangelands and especially transportation corridors, where it causes increased wildfire and many other environmental issues. Methods of reducing exotic annual grasses and restoring native perennials are needed, particularly testing of their intended target or unintended, non-target effects. In a series of experiments arrayed across different site and plant-community conditions on Idaho Transportation Department right-of-ways, the effects of chemical or biological herbicides, site preparation and co-treatments such as raking, and/or seeding were evaluated over 3 years. Strains of the soil bacterium Pseudomonas fluorescens that are supposedly weed-suppressive were generally ineffective, and resulted in relatively weak effects at a small proportion of plots and only at one site, but also resulted in highly undesirable non-target effects at another site. The chemical herbicides imazapic and especially indaziflam (Rejuvra) tended to have more consistent and stronger effects, and indaziflam furthermore provided a longer period of control, although additional years of observation would be required to assess its endurance. Seeding effects were weak, and preparation of seed conclusion, indaziflam appeared to be the most effective tool for reducing cheatgrass, but techniques for increasing perennials after its application are needed

    Snowmelt Timing Regulates Community Composition, Phenology, and Physiological Performance of Alpine Plants

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    The spatial patterning of alpine plant communities is strongly influenced by the variation in physical factors such as temperature and moisture, which are strongly affected by snow depth and snowmelt patterns. Earlier snowmelt timing and greater soil-moisture limitations may favor wide-ranging species adapted to a broader set of ecohydrological conditions than alpine-restricted species. We asked how plant community composition, phenology, plant water relations, and photosynthetic gas exchange of alpine-restricted and wide-ranging species differ in their responses to a ca. 40-day snowmelt gradient in the Colorado Rocky Mountains (Lewisia pygmaea, Sibbaldia procumbens, and Hymenoxys grandiflora were alpine-restricted and Artemisia scopulorum, Carex rupestris, and Geum rossii were wide-ranging species). As hypothesized, species richness and foliar cover increased with earlier snowmelt, due to a greater abundance of wide-ranging species present in earlier melting plots. Flowering initiation occurred earlier with earlier snowmelt for 12 out of 19 species analyzed, while flowering duration was shortened with later snowmelt for six species (all but one were wide-ranging species). We observed >50% declines in net photosynthesis from July to September as soil moisture and plant water potentials declined. Early-season stomatal conductance was higher in wide-ranging species, indicating a more competitive strategy for water acquisition when soil moisture is high. Even so, there were no associated differences in photosynthesis or transpiration, suggesting no strong differences between these groups in physiology. Our findings reveal that plant species with different ranges (alpine-restricted vs. wide-ranging) could have differential phenological and physiological responses to snowmelt timing and associated soil moisture dry-down, and that alpine-restricted species’ performance is more sensitive to snowmelt. As a result, alpine-restricted species may serve as better indicator species than their wide-ranging heterospecifics. Overall, alpine community composition and peak % cover are strongly structured by spatio-temporal patterns in snowmelt timing. Thus, near-term, community-wide changes (or variation) in phenology and physiology in response to shifts in snowmelt timing or rates of soil dry down are likely to be contingent on the legacy of past climate on community structure

    Hematologic Safety of Radium-223 Dichloride: Baseline Prognostic Factors Associated With Myelosuppression in the ALSYMPCA Trial.

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    BACKGROUND: Myelosuppression is common in patients with progressive castration-resistant prostate cancer and bone metastases. Radium-223 prolongs overall survival in these patients but may cause myelosuppression; understanding risk factors will improve clinical decision making. We describe hematologic safety of radium-223 in ALSYMPCA and post hoc analyses identifying patients at increased risk for hematologic toxicity. PATIENTS AND METHODS: Hematologic parameters and adverse events were analyzed. Multivariate analyses assessing baseline risk factors for hematologic toxicities were performed separately for radium-223 and placebo patients. RESULTS: Nine hundred one patients received radium-223 (n = 600) or placebo (n = 301); 65% of radium-223 and 48% of placebo patients had the full 6 cycles. Grade 3/4 thrombocytopenia was more common in radium-223 versus placebo patients (6% vs. 2%). Logistic regression analyses identified significant baseline predictors for grade 2-4 hematologic toxicities related to radium-223 treatment: extent of disease (6-20 vs. < 6 bone metastases; odds ratio [OR] = 2.76; P = .022) and elevated prostate-specific antigen (OR = 1.65; P = .006) for anemia; prior docetaxel (OR = 2.16; P = .035), decreased hemoglobin (OR = 1.35; P = .008), and decreased platelets (OR = 1.44; P = .030) for thrombocytopenia. Neutropenia events were too few in placebo patients for a comparative analysis. There were no significant associations between hematologic toxicities and number of radium-223 injections received (4-6 vs. 1-3). CONCLUSION: Radium-223 has a favorable safety profile with a low myelosuppression incidence. Understanding baseline factors associated with myelosuppression may assist clinicians in avoiding severe myelosuppression events with radium-223

    Design, synthesis, and biological evaluation of new thalidomide–donepezil hybrids as neuroprotective agents targeting cholinesterases and neuroinflammation

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    A new series of eight multifunctional thalidomide–donepezil hybrids were synthesized based on the multi target-directed ligand strategy and evaluated as potential neuroprotective, cholinesterase inhibitors and anti neuroinflammatory agents against neurodegenerative diseases. A molecular hybridization approach was used for structural design by combining the N-benzylpiperidine pharmacophore of donepezil and the isoindoline 1,3-dione fragment from the thalidomide structure. The most promising compound, PQM-189 (3g), showed good AChE inhibitory activity with an IC50 value of 3.15 ÎŒM, which was predicted by docking studies as interacting with the enzyme in the same orientation observed in the AChE–donepezil complex and a similar profile of interaction. Additionally, compound 3g significantly decreased iNOS and IL-1ÎČ levels by 43% and 39%, respectively, after 24 h of incubation with lipopolysaccharide. In vivo data confirmed the ability of 3g to prevent locomotor impairment and changes in feeding behavior elicited by lipopolysaccharide. Moreover, the PAMPA assay evidenced adequate blood–brain barrier and gastrointestinal tract permeabilities with an Fa value of 69.8%. Altogether, these biological data suggest that compound 3g can treat the inflammatory process and oxidative stress resulting from the overexpression of iNOS and therefore the increase in reactive nitrogen species, and regulate the release of pro-inflammatory cytokines such as IL-1ÎČ. In this regard, compound PQM-189 (3g) was revealed to be a promising neuroprotective and anti-neuroinflammatory agent with an innovative thalidomide–donepezil-based hybrid molecular architectur

    Episodic Occurrence of Favourable Weather Constrains Recovery of a Cold Desert Shrubland After Fire

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    Key to the long-term resilience of dryland ecosystems is the recovery of foundation plant species following disturbance. In ecosystems with high interannual weather variability, understanding the influence of short-term environmental conditions on establishment of foundation species is essential for identifying vulnerable landscapes and developing restoration strategies. We asked how annual environmental conditions affect post-fire establishment of Artemisia tridentata, a shrub species that dominates landscapes across much of the western United States, and evaluated the influence of episodic establishment on population recovery. We collected A. tridentata stem samples from 33 plots in 12 prescribed fire sites that burned 8–11 years before sampling. We determined individual establishment years using annual growth rings. We measured seasonal soil environmental conditions at the study sites and asked if these conditions predicted annual establishment density. We then evaluated whether establishment patterns could be predicted by site-level climate or dominant subspecies. Finally, we tested the effect of the magnitude and frequency of post-fire establishment episodes on long-term population recovery. Annual post-fire recruitment of A. tridentata was driven by the episodic availability of spring soil moisture. Annual establishment was highest with wetter spring soils (relative influence [RI] = 19.4%) and later seasonal dry-down (RI = 11.8%) in the year of establishment. Establishment density declined greatly 4 to 5 years after fire (RI = 17.1%). Post-fire establishment patterns were poorly predicted by site-level mean climate (marginal R2 ≀ 0.18) and dominant subspecies (marginal R2 ≀ 0.43). Population recovery reflected the magnitude, but not the frequency, of early post-fire establishment pulses. Post-fire A. tridentata density and cover (measured 8–11 years after fire) were more strongly related to the magnitude of the largest establishment pulse than to establishment frequency, suggesting that population recovery may occur with a single favourable establishment year. Synthesis and applications. This study demonstrates the importance of episodic periods of favourable weather for long-term plant population recovery following disturbance. Management strategies that increase opportunities for seed availability to coincide with favourable weather conditions, such as retaining unburned patches or repeated seeding treatments, can improve restoration outcomes in high-priority areas
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