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51.
Jon P. Nelson 《Journal of Environmental Economics and Management》1979,6(4):320-331
The present study reports on the influence of aircraft noise on housing prices in the vicinity of six major U.S. airports, including San Francisco, St. Louis, Cleveland, New Orleans, San Diego, and Buffalo. The sampling procedures attempt to control for the effect of accessibility on location rent, and hence, housing prices. Regression results are reported for the individual samples and for a pooled sample consisting of 845 observations. The regression coefficients for aircraft noise are stable about their weighted mean and are comparable to coefficient estimates from the pooled sample. Dummy variables and partitioned regressions are used to test for remaining accessibility effects. 相似文献
52.
Statistical inference on patch-specific survival and movement rates from marked animals 总被引:1,自引:0,他引:1
Michael J. Conroy Jon E. Anderson Stephen L. Rathbun David G. Krementz 《Environmental and Ecological Statistics》1996,3(2):99-116
Empirical estimates of patch-specific survival and movement rates are needed to parametrize spatially explicit population
models, and for inference on the effects of habitat quality and fragmentation on populations. Data from radio-marked animals,
in which both the fates and habitat locations of animals are known over time, can be used in conjunction with continuous-time
proportional hazards models to obtain inferences on survival rates. Discrete-time conditional logistic models may provide
inference on both survival and movement rates. We use Monte Carlo simulation to investigate accuracy of estimates of survival
from both approaches, and movement rates from conditional logistic regression, for two habitats. Bias was low (relative bias
< 0.04) and interval coverage accurate (close to the nominal 0.95) for estimates of habitat effect on survival based on proportional
hazards. Bias was high (
relative bias 0.60) and interval coverage poor (
= 0.26 vs. nominal 0.95) for estimates of habitat effect based on conditional logistic regression; bias was especially influenced
by heterogeneity in survival and the shape of the hazard function, whereas both bias and coverage were affected by ‘memory’
effects in movement patterns. Bias estimates of movement rate was low (
relative bias < 0.05), but interval coverage was poor (
= 0.48–0.80), possibly as a result of poor performance of a Taylor series estimate of variance. An example is provided from
a radio-telemetry study of 47 wintering American woodcock (Scolopax minor), illustrating practical difficulties in field studies to parametrize these models. We also discuss extensions of continuous-time
models to explicitly include a movement process, and further examine tradeoffs between continuous and discrete models. 相似文献
53.
Elie Gaget Diego Pavón-Jordán Alison Johnston Aleksi Lehikoinen Wesley M. Hochachka Brett K. Sandercock Alaaeldin Soultan Hichem Azafzaf Nadjiba Bendjedda Taulant Bino Luka Božič Preben Clausen Mohamed Dakki Koen Devos Cristi Domsa Vitor Encarnação Kiraz Erciyas-Yavuz Sándor Faragó Teresa Frost Clemence Gaudard Lívia Gosztonyi Fredrik Haas Menno Hornman Tom Langendoen Christina Ieronymidou Vasiliy A. Kostyushin Lesley J. Lewis Svein-Håkon Lorentsen Leho Luigujõe Włodzimierz Meissner Tibor Mikuska Blas Molina Zuzana Musilová Viktor Natykanets Jean-Yves Paquet Nicky Petkov Danae Portolou Jozef Ridzoň Samir Sayoud Marko Šćiban Laimonas Sniauksta Antra Stīpniece Nicolas Strebel Norbert Teufelbauer Goran Topić Danka Uzunova Andrej Vizi Johannes Wahl Marco Zenatello Jon E. Brommer 《Conservation biology》2021,35(3):834-845
Climate warming is driving changes in species distributions and community composition. Many species have a so-called climatic debt, that is, shifts in range lag behind shifts in temperature isoclines. Inside protected areas (PAs), community changes in response to climate warming can be facilitated by greater colonization rates by warm-dwelling species, but also mitigated by lowering extirpation rates of cold-dwelling species. An evaluation of the relative importance of colonization-extirpation processes is important to inform conservation strategies that aim for both climate debt reduction and species conservation. We assessed the colonization-extirpation dynamics involved in community changes in response to climate inside and outside PAs. To do so, we used 25 years of occurrence data of nonbreeding waterbirds in the western Palearctic (97 species, 7071 sites, 39 countries, 1993–2017). We used a community temperature index (CTI) framework based on species thermal affinities to investigate species turnover induced by temperature increase. We determined whether thermal community adjustment was associated with colonization by warm-dwelling species or extirpation of cold-dwelling species by modeling change in standard deviation of the CTI (CTISD). Using linear mixed-effects models, we investigated whether communities in PAs had lower climatic debt and different patterns of community change than communities outside PAs. For CTI and CTISD combined, communities inside PAs had more species, higher colonization, lower extirpation, and lower climatic debt (16%) than communities outside PAs. Thus, our results suggest that PAs facilitate 2 independent processes that shape community dynamics and maintain biodiversity. The community adjustment was, however, not sufficiently fast to keep pace with the large temperature increases in the central and northeastern western Palearctic. Our results underline the potential of combining CTI and CTISD metrics to improve understanding of the colonization-extirpation patterns driven by climate warming. 相似文献
54.
Influence of sediment on the fate and toxicity of a polyethoxylated tallowamine surfactant system (MON 0818) in aquatic microcosms 总被引:1,自引:0,他引:1
Wang N Besser JM Buckler DR Honegger JL Ingersoll CG Johnson BT Kurtzweil ML Macgregor J McKee MJ 《Chemosphere》2005,59(4):545-551
The fate and toxicity of a polyethoxylated tallowamine (POEA) surfactant system, MON 0818, was evaluated in water-sediment microcosms during a 4-d laboratory study. A surfactant solution of 8 mg l(-1) nominal concentration was added to each of nine 72-l aquaria with or without a 3-cm layer of one of two natural sediments (total organic carbon (TOC) 1.5% or 3.0%). Control well water was added to each of nine additional 72-l aquaria with or without sediment. Water samples were collected from the microcosms after 2, 6, 24, 48, 72, and 96 h of aging to conduct 48-h toxicity tests with Daphnia magna and to determine surfactant concentrations. Elevated mortality of D. magna (43-83%) was observed in overlying water sampled from water-only microcosms throughout the 96-h aging period, whereas elevated mortality (23-97%) was only observed in overlying water sampled from water-sediment microcosms during the first 24h of aging. Measured concentrations of MON 0818 in water-only microcosms remained relatively constant (4-6 mg l(-1)) during the 96-h period, whereas the concentrations in overlying water from microcosms containing either of the two types of sediment dissipated rapidly, with half-lives of 13 h in the 3.0% TOC sediment and 18 h in the 1.5% TOC sediment. Both toxicity and the concentration of MON 0818 in overlying water decreased more rapidly in microcosms containing sediment with the higher percent TOC and clay and with a higher microbial biomass. Mortality of D. magna was significantly correlated with surfactant concentrations in the overlying water. These results indicate that the toxicity of the POEA surfactant in water rapidly declines in the presence of sediment due to a reduction in the surfactant concentration in the overlying water above the sediment. 相似文献
55.
Sylvain Giroud Alina L. Evans Isabelle Chery Fabrice Bertile Georg Tascher Justine Bertrand-Michel Guillemette Gauquelin-Koch Jon M Arnemo Jon E. Swenson Etienne Lefai Stéphane Blanc Chantal Simon 《Die Naturwissenschaften》2018,105(9-10):58
Polyunsaturated fatty acids (PUFAs) exert several important functions across organ systems. During winter, hibernators divert PUFAs from oxidation, retaining them in their tissues and membranes, to ensure proper body functions at low body temperature. PUFAs are also precursors of eicosanoids with pro- and anti-inflammatory properties. This study investigated seasonal changes in eicosanoid metabolism of free-ranging brown bears (Ursus arctos). By using a lipidomic approach, we assessed (1) levels of specific omega-3 and omega-6 fatty acids involved in the eicosanoid cascade and (2) concentrations of eicosanoids in skeletal muscle and blood plasma of winter hibernating and summer active bears. We observed significant seasonal changes in the specific omega-3 and omega-6 precursors. We also found significant seasonal alterations of eicosanoid levels in both tissues. Concentrations of pro-inflammatory eicosanoids, such as thromboxane B2, 5-hydroxyeicosatetraenoic acid (HETE), and 15-HETE and 18-HETE, were significantly lower in muscle and/or plasma of hibernating bears compared to summer-active animals. Further, plasma and muscle levels of 5,6-epoxyeicosatrienoic acid (EET), as well as muscle concentration of 8,9-EET, tended to be lower in bears during winter hibernation vs. summer. We also found lower plasma levels of anti-inflammatory eicosanoids, such as 15dPGJ2 and PGE3, in bears during winter hibernation. Despite of the limited changes in omega-3 and omega-6 precursors, plasma and muscle concentrations of the products of all pathways decreased significantly, or remained unchanged, independent of their pro- or anti-inflammatory properties. These findings suggest that hibernation in bears is associated with a depressed state of the eicosanoid cascade. 相似文献
56.
Peter J. Silk Krista Ryall D. Barry Lyons Jon Sweeney Junping Wu 《Die Naturwissenschaften》2009,96(5):601-608
Analyses of the elytral hydrocarbons from male and female emerald ash borer, Agrilus planipennis Fairmaire, that were freshly emerged vs. sexually mature (>10 days old) revealed a female-specific compound, 9-methyl-pentacosane
(9-Me-C25), only present in sexually mature females. This material was synthesized by the Wittig reaction of 2-decanone with (n-hexadecyl)-triphenylphosphonium bromide followed by catalytic reduction to yield racemic 9-Me C25, which matched the natural compound by gas chromatography/mass spectrometry (retention time and EI mass spectrum). In field
bioassays with freeze-killed sexually mature A. planipennis females, feral males spent significantly more time in contact and attempting copulation with unwashed females than with females
that had been washed in n-hexane to remove the cuticular lipids. Hexane-washed females to which 9-Me-C25 had been reapplied elicited similar contact time and percentage of time attempting copulation as unwashed females, indicating
that 9-methyl-pentacosane is a contact sex pheromone component of A. planipennis. This is the first contact sex pheromone identified in the Buprestidae. 相似文献
57.
The construct collective psychological ownership is introduced. Reflecting the psychology of “us” and “ours,” collective psychological ownership emerges through interactive dynamics whereby individuals come to a single and shared mind‐set as it relates to a sense of ownership for a particular object. After providing a conceptual definition for the construct, we turn our attention to a detailed elaboration of the construct, offering comments on its genesis, emergent context, underlying motives, and a discussion of what can and cannot be owned. We also provide a discussion of the dynamics associated with its formation, highlighting the paths down which groups travel that influence the emergence of this psychological state. Next, we turn our attention to the emergence of collective psychological ownership within the organizational and teamwork context paying particular attention to the role of work environment structure. We conclude with a discussion of a set of work‐related attitudinal, motivational, behavioral, and stress‐related outcomes that stem from this psychological state. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
58.
59.
Jon E. Brommer 《Behavioral ecology and sociobiology》2013,67(10):1709-1718
Studies increasingly explore whether there is variation between individuals in how they adjust their behavior to different environmental contexts using random regression analysis (RR). RR estimates the between-individual variance in elevation (expected behavior in the mean environment) and variance in plasticity (individual-specific adjustment of behavior to the environment) and the covariance between these properties. These (co)variances allow deriving both environment-specific repeatability estimates and the individual-level correlation in behavior between environmental conditions, both of which are of key interest for understanding consistency in behavior over space and time, a core issue in animal personality research. However, very few studies use the RR estimates to produce this information. In this paper, I outline how to extract this information (including example code in R) and apply the approach to 16 estimates based on nine published RR studies. Despite the fact that the behaviors have a decent repeatability under different environmental conditions, I find that in half the cases, the cross-environmental correlation is low (<0.4). This implies that individuals differ in their behavioral trait values but that the ranking of these individual values tends to change between environmental conditions. This level of inconsistency in animal personality traits appears not to have been fully appreciated, and future studies on plasticity using RR should explicitly include it. 相似文献
60.
Most plants attract multiple flower visitors that may vary widely in their effectiveness as pollinators. Floral evolution is expected to reflect interactions with the most important pollinators, but few studies have quantified the contribution of different pollinators to current selection on floral traits. To compare selection mediated by diurnal and nocturnal pollinators on floral display and spur length in the rewarding orchid Gymnadenia conopsea, we manipulated the environment by conducting supplemental hand-pollinations and selective pollinator exclusions in two populations in central Norway. In both populations, the exclusion of diurnal pollinators significantly reduced seed production compared to open pollination, whereas the exclusion of nocturnal pollinators did not. There was significant selection on traits expected to influence pollinator attraction and pollination efficiency in both the diurnal and nocturnal pollination treatment. The relative strength of selection among plants exposed to diurnal and nocturnal visitors varied among traits and populations, but the direction of selection was consistent. The results suggest that diurnal pollinators are more important than nocturnal pollinators for seed production in the study populations, but that both categories contribute to selection on floral morphology. The study illustrates how experimental manipulations can link specific categories of pollinators to observed selection on floral traits, and thus improve our understanding of how species interactions shape patterns of selection. 相似文献