1,003 research outputs found
Choosing the best of both worlds
The great crested newt (Triturus cristatus) is dependent on two environments for its survival: the aquatic habitat necessary for breeding and development, and the terrestrial
habitat required for post-breeding and juvenile activities. For a population to be able to survive in a landscape, both habitat types must be present within migration distance
from each other. The overall aim of this thesis is to find and describe prerequisites of environments and landscapes that make them sufficient as habitats for the great crested
newt. The purpose is also to present the results in a conservation perspective and to discuss them in relation to practical examples. In five separate studies, performed in
Örebro County, south-central Sweden, the aquatic and terrestrial habitats of the species were examined. The first study examined aquatic plants in a variety of ponds and landscapes, to determine if the diversity of plant species was higher in ponds where great crested newts were present. I found that ponds with newts had a significantly
higher mean number of plant species than ponds without the species. The second study focused on the question if there are chemical and physical characteristics that determine
occurrence of great crested newts. The results showed that temperature and nutrient levels (nitrogen and phosphorus) were important in distinguishing between ponds with
and without newts, whereas other physical variables were less important. My results also suggest that the great crested newt selects ponds with low nutrient levels for
breeding, while the species may also be present in ponds with higher nutrient levels. The third study used radio-telemetry in an attempt to determine how the great crested
newt moved in its terrestrial habitat and which micro-habitats it used while the focal point of study four was the landscape and if landscape composition may predict use of ponds as aquatic habitats. Combined, studies three and four suggest that management of the species should to a greater extent include terrestrial habitat, with special attention given to older, deciduous-rich forest within approximately 200 m of breeding ponds. The aim of the last study was to describe and evaluate a project concerning
translocation of a great crested newt population. I point out the necessity of long-term monitoring to distinguish any possible success with respect to site sustainability and
population size
Combining Consumer Valuation Research with Sensory Science Techniques: A Laboratory Experiment
In this research, we integrated an experimental auction with sensory science techniques—namely, trained sensory panels used to analyze the sensory attributes of wines—to examine the effects of objective and sensory information in the market for California-produced Cabernet Sauvignons. The experiment permitted observation of consumer valuation for sensory attributes of wine, appellations, expert ratings, and wineries. Participants submitted bids each time they received new information about the wines. The balanced experimental design permits evaluation of the effects of consumer characteristics on attribute valuation. We had 236 people participate in the research, which consisted of nine rounds of bidding and one round of hedonic liking scores. Rounds 5-9 repeated the structure of information released in rounds 1-4, but added sensory information, yielding 472 observations for each type of information (e.g. appellation, expert rating, winery). We obtain a total of 8496 valuations, or bids and 944 hedonic “liking” ratings, as well as demographic information, wine consumption data, and a wine knowledge score for each consumer. The results of the research agree with many of the previously held notions about valuation of wine by consumers. Participants value Cabernet Sauvignons from Napa Valley and Sonoma County and their sub-appellations more than wines labeled with the California appellation. Bids for wines rated by experts such as the Wine Advocate (Robert Parker) or Wine Spectator increased as the experts’ ratings increased. However, we also find that consumer characteristics are very important in explaining WTP for wine attributes. The contributions of prestigious appellations to the value of Cabernet Sauvignons depended on consumer characteristics. Willingness to pay was highly correlated with sensory evaluation, but even after tasting the wine, appellation and expert ratings still mattered for WTP. Overall, the research describes a significant amount of heterogeneity in the preferences for sensory characteristics of wine, and that individual characteristics systematically explain many of the differences in valuation of wine attributes.Experimental Economics, Willingness to Pay, WTP, Wine, Consumer Valuation, Hedonic Pricing, Sensory Analysis, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Marketing, Research Methods/ Statistical Methods,
Process, People, Power and Conflict: Some Lessons from a Participatory Policy Process in Andhra Pradesh, India
A large body of empirical literature highlights the need for stakeholder participation within the context of policy change and democratic governance. This makes intuitive sense and may appear to be a straightforward process of managing conflicting interests, building consensus, and lining up support. The reality, however, is often much more complicated and conflictive, even where there is general agreement on the policy objectives. The present paper examines these issues in the context of participatory policy development for the delivery of veterinary services by para-professionals in the Indian state of Andhra Pradesh. It illustrates the challenges inherent in the politics of participatory policy processes and the potential of ‘agenda hijack’ by influential partners, resulting in missed learning opportunities. It also offers insights on practical steps to counter these dangers, as potential lessons for practitioners and project managers engaged in participatory policy reform processes.
Collisional and dynamic evolution of dust from the asteroid belt
The size and spatial distribution of collisional debris from main belt asteroids is modeled over a 10 million year period. The model dust and meteoroid particles spiral toward the Sun under the action of Poynting-Robertson drag and grind down as they collide with a static background of field particles
Genetic Diversity and Competitive Abilities of Dalea Purpurea (Fabaceae) from Remnant and Restored Grasslands
Allozyme and randomly amplified polymorphic DNA (RAPD) analyses were used to characterize the genetic relationships of Dalea purpurea from remnant and restored Illinois tallgrass prairies and a large remnant tallgrass prairie in Kansas. The remnant Illinois populations were less genetically diverse than the restored Illinois populations and the Kansas population. These restored Illinois populations were established with at least two seed sources that were locally collected. There was little population divergence (Fst = 0.042), which ST is consistent with other perennial forbs, while the genetic relationships among populations reflected geographic proximity. In a greenhouse competition experiment, differences in performance between seedlings was not related to the remnant or restored status of Illinois populations, but plants from Kansas were significantly smaller than Illinois plants. Genetic diversity and competitive ability were not associated with the size of the original source population. Our data indicate that using multiple local seed sources for restoration projects will maintain the local gene pool while enhancing the regional genetic diversity of this species
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In vivo and in vitro assessment of mirtazapine pharmacokinetics in cats with liver disease.
BackgroundLiver disease (LD) prolongs mirtazapine half-life in humans, but it is unknown if this occurs in cats with LD and healthy cats.Hypothesis/objectivesTo determine pharmacokinetics of administered orally mirtazapine in vivo and in vitro (liver microsomes) in cats with LD and healthy cats.AnimalsEleven LD and 11 age-matched control cats.MethodsCase-control study. Serum was obtained 1 and 4 hours (22 cats) and 24 hours (14 cats) after oral administration of 1.88 mg mirtazapine. Mirtazapine concentrations were measured by liquid chromatography with tandem mass spectrometry. Drug exposure and half-life were predicted using limited sampling modeling and estimated using noncompartmental methods. in vitro mirtazapine pharmacokinetics were assessed using liver microsomes from 3 LD cats and 4 cats without LD.ResultsThere was a significant difference in time to maximum serum concentration between LD cats and control cats (median [range]: 4 [1-4] hours versus 1 [1-4] hours; P = .03). The calculated half-life of LD cats was significantly prolonged compared to controls (median [range]: 13.8 [7.9-61.4] hours versus 7.4 [6.7-9.1] hours; P < .002). Mirtazapine half-life was correlated with ALT (P = .002; r = .76), ALP (P < .0001; r = .89), and total bilirubin (P = .0008; r = .81). The rate of loss of mirtazapine was significantly different between microsomes of LD cats (-0.0022 min-1 , CI: -0.0050 to 0.00054 min-1 ) and cats without LD (0.01849 min-1 , CI: -0.025 to -0.012 min-1 ; P = .002).Conclusions and clinical importanceCats with LD might require less frequent administration of mirtazapine than normal cats
The origin and evolution of the zodiacal dust cloud
We have now analyzed a substantial fraction of the IRAS observations of the zodiacal cloud, particularly in the 25 micron waveband. We have developed a gravitational perturbation theory that incorporates the effects of Poynting-Robertson light drag (Gomes and Dermott, 1992). We have also developed a numerical model, the SIMUL mode, that reproduces the exact viewing geometry of the IRAS telescope and calculates the distribution of thermal flux produced by any particular distribution of dust particle orbits (Dermott and Nicholson, 1989). With these tools, and using a distribution of orbits based on those of asteroidal particles with 3.4 micron radii whose orbits decay due to Poynting-Robertson light drag and are perturbed by the planets, we have been able to: (1) account for the inclination and node of the background zodiacal cloud observed by IRAS in the 25 micron waveband; (2) relate the distribution of orbits in the Hirayama asteroid families to the observed shapes of the IRAS solar system dustbands; and (3) show that there is observational evidence in the IRAS data for the transport of asteroidal particles from the main belt to the Earth by Poynting-Robertson light drag
Bayesian joint inversion of controlled source electromagnetic and magnetotelluric data to image freshwater aquifer offshore New Jersey
Author Posting. © The Authors, 2019. This article is posted here by permission of The Royal Astronomical Society for personal use, not for redistribution. The definitive version was published in Geophysical Journal International 218(3), (2019): 1822-1837, doi: 10.1093/gji/ggz253.Joint inversion of multiple electromagnetic data sets, such as controlled source electromagnetic and magnetotelluric data, has the potential to significantly reduce uncertainty in the inverted electrical resistivity when the two data sets contain complementary information about the subsurface. However, evaluating quantitatively the model uncertainty reduction is made difficult by the fact that conventional inversion methods—using gradients and model regularization—typically produce just one model, with no associated estimate of model parameter uncertainty. Bayesian inverse methods can provide quantitative estimates of inverted model parameter uncertainty by generating an ensemble of models, sampled proportional to data fit. The resulting posterior distribution represents a combination of a priori assumptions about the model parameters and information contained in field data. Bayesian inversion is therefore able to quantify the impact of jointly inverting multiple data sets by using the statistical information contained in the posterior distribution. We illustrate, for synthetic data generated from a simple 1-D model, the shape of parameter space compatible with controlled source electromagnetic and magnetotelluric data, separately and jointly. We also demonstrate that when data sets contain complementary information about the model, the region of parameter space compatible with the joint data set is less than or equal to the intersection of the regions compatible with the individual data sets. We adapt a trans-dimensional Markov chain Monte Carlo algorithm for jointly inverting multiple electromagnetic data sets for 1-D earth models and apply it to surface-towed controlled source electromagnetic and magnetotelluric data collected offshore New Jersey, USA, to evaluate the extent of a low salinity aquifer within the continental shelf. Our inversion results identify a region of high resistivity of varying depth and thickness in the upper 500 m of the continental shelf, corroborating results from a previous study that used regularized, gradient-based inversion methods. We evaluate the joint model parameter uncertainty in comparison to the uncertainty obtained from the individual data sets and demonstrate quantitatively that joint inversion offers reduced uncertainty. In addition, we show how the Bayesian model ensemble can subsequently be used to derive uncertainty estimates of pore water salinity within the low salinity aquifer.We gratefully acknowledge funding support from National Science Foundation grants 1458392 and 1459035. We thank the captain and crew of the R.V. Marcus G. Langseth for a successful cruise and the Marine EM Lab at Scripps Institution of Oceanography for providing the instrumentation. We also thank Chris Armerding, Marah Dahn, John Desanto, Jimmy Elsenbeck, Matt Folsom, Keiichi Ishizu, Jeff Pepin, Charlotte Wiman and Georgie Zelenak for participating in the cruise. We gratefully acknowledge Alberto Malinverno for the idea to use a Monte Carlo scheme to estimate the distribution of pore fluid salinity, and William Menke for many constructive conversations and suggestions
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