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1.
Historically, many species moved great distances as climates changed. However, modern movements will be limited by the patterns of human‐dominated landscapes. Here, we use a combination of projected climate‐driven shifts in the distributions of 2903 vertebrate species, estimated current human impacts on the landscape, and movement models, to determine through which areas in the western hemisphere species will likely need to move to track suitable climates. Our results reveal areas with projected high densities of climate‐driven movements – including, the Amazon Basin, the southeastern United States and southeastern Brazil. Some of these regions, such as southern Bolivia and northern Paraguay, contain relatively intact landscapes, whereas others such as the southeastern United States and Brazil are heavily impacted by human activities. Thus, these results highlight both critical areas for protecting lands that will foster movement, and barriers where human land‐use activities will likely impede climate‐driven shifts in species distributions. 相似文献
2.
美国生命科学两用性研究监管政策分析 总被引:2,自引:0,他引:2
目的:近年来高致病性禽流感H5N1病毒基因改造研究及美国国家生物安全科学咨询委员会的监管建议引起广泛争议,美国发布了生命科学两用性研究监管政策。本研究旨在通过对美国生命科学两用性研究监管政策进行分析,探讨两用性研究发展和监管趋势。方法:通过文献检索,获取生命科学两用性研究监管政策相关的情报源,对美国政府生命科学两用性研究监管的政策背景、主要内容、政策评论、政策动因进行系统梳理与分析。结果:美国政府出台的生命科学两用性研究监管政策,有助于美国对整个生命科学研究周期(从最初提交资助申请到研究结论和研究成果交流)潜在的误用风险进行管理。结论:美国生命科学两用性研究引发极大争议,两用性研究监管主要依靠生命科学团体的自我管理,政策具有指导性而非强制性。 相似文献
3.
Stephen N. Matthews Louis R. Iverson Anantha M. Prasad Matthew P. Peters 《Ecography》2011,34(6):933-945
Mounting evidence shows that organisms have already begun to respond to global climate change. Advances in our knowledge of how climate shapes species distributional patterns has helped us better understand the response of birds to climate change. However, the distribution of birds across the landscape is also driven by biotic and abiotic components, including habitat characteristics. We therefore developed statistical models of 147 bird species distributions in the eastern United States, using climate, elevation, and the distributions of 39 tree species to predict contemporary bird distributions. We used randomForest, a robust regression‐based decision tree ensemble method to predict contemporary bird distributions. These models were then projected onto three models of climate change under high and low emission scenarios for both climate and the projected change in suitable habitat for the 39 tree species. The resulting bird species models indicated that breeding habitat will decrease by at least 10% for 61–79 species (depending on model and emissions scenario) and increase by at least 10% for 38–52 species in the eastern United States. Alternatively, running the species models using only climate/elevation (omitting tree species), we found that the predictive power of these models was significantly reduced (p<0.001). When these climate/elevation‐only models were projected onto the climate change scenarios, the change in suitable habitat was more extreme in 60% of the species. In the end, the strong associations with vegetation tempers a climate/elevation‐only response to climate change and indicates that refugia of suitable habitat may persist for these bird species in the eastern US, even after the redistribution of tree species. These results suggest the importance of interacting biotic processes and that further fine‐scale research exploring how climate change may disrupt species specific requirements is needed. 相似文献
4.
Modeled ecohydrological responses to climate change at seven small watersheds in the northeastern United States
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Afshin Pourmokhtarian Charles T. Driscoll John L. Campbell Katharine Hayhoe Anne M. K. Stoner Mary Beth Adams Douglas Burns Ivan Fernandez Myron J. Mitchell James B. Shanley 《Global Change Biology》2017,23(2):840-856
A cross‐site analysis was conducted on seven diverse, forested watersheds in the northeastern United States to evaluate hydrological responses (evapotranspiration, soil moisture, seasonal and annual streamflow, and water stress) to projections of future climate. We used output from four atmosphere–ocean general circulation models (AOGCMs; CCSM4, HadGEM2‐CC, MIROC5, and MRI‐CGCM3) included in Phase 5 of the Coupled Model Intercomparison Project, coupled with two Representative Concentration Pathways (RCP 8.5 and 4.5). The coarse resolution AOGCMs outputs were statistically downscaled using an asynchronous regional regression model to provide finer resolution future climate projections as inputs to the deterministic dynamic ecosystem model PnET‐BGC. Simulation results indicated that projected warmer temperatures and longer growing seasons in the northeastern United States are anticipated to increase evapotranspiration across all sites, although invoking CO2 effects on vegetation (growth enhancement and increases in water use efficiency (WUE)) diminish this response. The model showed enhanced evapotranspiration resulted in drier growing season conditions across all sites and all scenarios in the future. Spruce‐fir conifer forests have a lower optimum temperature for photosynthesis, making them more susceptible to temperature stress than more tolerant hardwood species, potentially giving hardwoods a competitive advantage in the future. However, some hardwood forests are projected to experience seasonal water stress, despite anticipated increases in precipitation, due to the higher temperatures, earlier loss of snow packs, longer growing seasons, and associated water deficits. Considering future CO2 effects on WUE in the model alleviated water stress across all sites. Modeled streamflow responses were highly variable, with some sites showing significant increases in annual water yield, while others showed decreases. This variability in streamflow responses poses a challenge to water resource management in the northeastern United States. Our analyses suggest that dominant vegetation type and soil type are important attributes in determining future hydrological responses to climate change. 相似文献
5.
Interviews with 98 Canadian-trained basic medical scientists currently employed in the United States reveal that they were attracted to the United States by the belief that greater career opportunities exist in the United States than in Canada.They attributed the failure on the part of Canada to attract scientists to Canada and to retain their own graduates to: (1) Poor recruiting methods and a failure on the part of Canadian employees to keep in touch with Canadian scientists in American graduate and postgraduate training positions. (2) Scarcity of research funds. (3) Lack of opportunity in Canada occasioned by the smaller number of medical schools and medical research institutions as compared to the United States. (4) The negative conservatism of Canadian academic circles occasioned by academic inbreeding, anti-Semitism, Anglophilia and the tight control of research, research funds and university appointments by an oldguard “establishment”. 相似文献
6.
Rosypal AC Hill R Lewis S Barr SC Valadas S Gennari SM Lindsay DS 《The Journal of parasitology》2011,97(1):140-143
Dogs are reservoir hosts for Trypanosoma cruzi , the causative agent of American trypanosomiasis. A rapid immunochromatographic dipstick test (ICT) is available commercially for canine serological testing. The ICT was developed with the use of sera from South American dogs, but it is not routinely used in the United States. We evaluated the utility of the ICT in detecting anti-T. cruzi antibodies in dogs from the United States. Dogs (N = 64) were experimentally infected with United States' isolates of T. cruzi from an opossum (Didelphis virginiana), an armadillo (Dasypus novemcinctus), and a domestic dog (Canis familiaris), and were tested after experimental infection. Sera from uninfected United States dogs (n = 79; hemaculture negative) were used as negative controls. In a blind study, sera were tested by the ICT and compared to the indirect immunofluorescent antibody test with the use of Brazil-strain epimastigotes as antigen. The sensitivity of the ICT was 91% and the specificity was 98% in dogs experimentally infected with United States isolates. Our study indicates that the ICT could be a useful screening tool for serological surveillance of canine T. cruzi exposure in the United States. 相似文献
7.
Kenneth W. Stolte 《人类与生态风险评估》2001,7(5):1297-1316
The Forest Health Monitoring (FHM) and Forest Inventory and Analyses (FIA) programs are integrated biological monitoring systems that use nationally standardized methods to evaluate and report on the health and sustainability of forest ecosystems in the United States. Many of the anticipated changes in forest ecosystems from climate change were also issues addressed in sections of FHM's National Technical Report 1991 to 1998. The integrated FHM and FIA monitoring systems are currently establishing baseline conditions (status and change) in most States for many of the expected effects, and are projected to have full implementation for all States and Territories in 2003. These monitoring systems utilize a broad suite of indicators of key ecosystem components and processes that are responsive to many biotic and abiotic stressors, including those anticipated from climate change. These programs will contribute essential information for many decades for many of the anticipated changes in forest ecosystem from increasing carbon dioxide concentrations, changing climatic scenarios, and extreme weather events that are probable in the next 30 to 100 years. 相似文献
8.
Alternative biomass strategies for bioenergy: implications for bird communities across the southeastern United States
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Isabel G. W. Gottlieb Robert J. Fletcher Jr Mauricio M. Nuñez‐Regueiro Holly Ober Lora Smith Berry J. Brosi 《Global Change Biology Bioenergy》2017,9(11):1606-1617
Concerns over energy demands and climate change have led the United States to set ambitious targets for bioenergy production in the coming decades. The southeastern United States has had a recent increase in biomass woody pellet production and is projected to produce a large portion of the nation's cellulosic biofuels. We conducted a large‐scale, systematic comparison of potential impacts of two types of bioenergy feedstocks – corn (Zea mays) and pine (Pinus spp.) – on bird communities across the southeastern United States. In addition, we evaluated three biomass alternatives for woody biomass from pine plantations: thinning, residue harvest, and short‐rotation energy plantations (SREPs). We conducted transect counts for birds in eight different land uses across the region (85 sites), including corn fields, reference forest, and plantation forests, 2013–2015. We then used hierarchical occupancy models to test the effect of these biomass alternatives on 31 species. Across all species, birds had lower rates of occupancy in corn fields compared to pine stands. Thinning had positive effects on the average occupancy across species, while residue harvest and the potential conversion of conventional plantations to SREPs had negative effects. Cavity nesters and species with bark‐gleaning foraging strategies tended to show the strongest responses. These results highlight the potential negative effects of corn as an energy crop relative to the use of pine biomass. In addition, harvesting biomass via thinning was a bird‐friendly harvest method in comparison with other alternatives. While SREPs may negatively impact some bird species, previously reported yields emphasize that they may provide an order of magnitude greater yield per unit area than other alternatives considered, such that this land‐use practice may be an important alternative to minimize the bioenergy impacts across the landscape. 相似文献
9.
Sebastián Martinuzzi Stephanie R. Januchowski‐Hartley Brenda M. Pracheil Peter B. McIntyre Andrew J. Plantinga David J. Lewis Volker C. Radeloff 《Global Change Biology》2014,20(1):113-124
Freshwater ecosystems provide vital resources for humans and support high levels of biodiversity, yet are severely threatened throughout the world. The expansion of human land uses, such as urban and crop cover, typically degrades water quality and reduces freshwater biodiversity, thereby jeopardizing both biodiversity and ecosystem services. Identifying and mitigating future threats to freshwater ecosystems requires forecasting where land use changes are most likely. Our goal was to evaluate the potential consequences of future land use on freshwater ecosystems in the coterminous United States by comparing alternative scenarios of land use change (2001–2051) with current patterns of freshwater biodiversity and water quality risk. Using an econometric model, each of our land use scenarios projected greater changes in watersheds of the eastern half of the country, where freshwater ecosystems already experience higher stress from human activities. Future urban expansion emerged as a major threat in regions with high freshwater biodiversity (e.g., the Southeast) or severe water quality problems (e.g., the Midwest). Our scenarios reflecting environmentally oriented policies had some positive effects. Subsidizing afforestation for carbon sequestration reduced crop cover and increased natural vegetation in areas that are currently stressed by low water quality, while discouraging urban sprawl diminished urban expansion in areas of high biodiversity. On the other hand, we found that increases in crop commodity prices could lead to increased agricultural threats in areas of high freshwater biodiversity. Our analyses illustrate the potential for policy changes and market factors to influence future land use trends in certain regions of the country, with important consequences for freshwater ecosystems. Successful conservation of aquatic biodiversity and ecosystem services in the United States into the future will require attending to the potential threats and opportunities arising from policies and market changes affecting land use. 相似文献
10.
Formerly used world-wide as a popular botanical medicine to reduce anxiety, reports of hepatotoxicity linked to consuming kava extracts in the late 1990s have resulted in global restrictions on kava use and have hindered kava-related research. Despite its presence on the United States Food and Drug Administration consumer advisory list for the past decade, export data from kava producing countries implies that US kava imports, which are not publicly reported, are both increasing and of a fairly high volume. We have measured the variability in extract chemical composition and cytotoxicity towards human lung adenocarcinoma A549 cancer cells of 25 commercially available kava products. Results reveal a high level of variation in chemical content and cytotoxicity of currently available kava products. As public interest and use of kava products continues to increase in the United States, efforts to characterize products and expedite research of this potentially useful botanical medicine are necessary. 相似文献
11.
David D. Reed Elizabeth A. Jones Hal O. Liechty Glenn D. Mroz Martin F. Jurgensen 《International journal of biometeorology》1992,36(1):51-57
The response of four northern deciduous tree species to annual climate variation is quantified at two intensively measured sites in northern Michigan, USA. Response to changes in temperature and moisture differ with the species and is dependent on other site conditions. Relationships identified in these field studies indicate that projected climate changes may have dramatic effects on the productivity of at least some commercially important tree species in the northern United States. 相似文献
12.
Roberts EF 《Medical anthropology quarterly》2011,25(2):232-253
When frozen embryos are publically debated in the United States, they are most often positioned as having two possible future trajectories: (1) as individual humans and (2) as contributors to stem cell research. Long-term embryo accumulation threatens both of these futures. An accumulated embryo is stuck in a clinic, held back from having an individual future or from contributing to science. There are other kinds of futures, though. For some patients in the United States and Ecuador, where I conducted ethnographic research, future reckoning involves a vision of responsibility toward embryos embedded within a specific family. For these patients, frozen embryo donation to another family or to science constitutes abandonment. The future at stake is not that of an individual embryo's life, but a group's future who would abandon one of its own. These patients would rather destroy embryos than freeze them for a future away from their relations. [Ecuador, United States, in 相似文献
13.
《Ethology and sociobiology》1987,8(3):221-247
The author illustrates the use of written legal opinions to test sociobiological hypotheses with a body of cases extending over 100 years in which judges from all over the United States appear to have been of the unanimous opinion that close genetic and in-law relationships were positively correlated to ongoing reciprocal aid-giving relationships. The universe of the sample projected in the judicial opinions included relatives and nonrelatives all living in the same household, so the possibility that such correlations could be attributed completely to the comparative geographic proximity that would be expected between close relatives is essentially eliminated. The author suggests that similar bodies of cases, which could be used to test behavioral hypotheses, exist in the more than three million indexed U.S. legal opinions. 相似文献
14.
Andrew B. Reinmann Jessica R. Susser Eleonora M. C. Demaria Pamela H. Templer 《Global Change Biology》2019,25(2):420-430
Changes in growing season climate are often the foci of research exploring forest response to climate change. By contrast, little is known about tree growth response to projected declines in winter snowpack and increases in soil freezing in seasonally snow‐covered forest ecosystems, despite extensive documentation of the importance of winter climate in mediating ecological processes. We conducted a 5‐year snow‐removal experiment whereby snow was removed for the first 4–5 weeks of winter in a northern hardwood forest at the Hubbard Brook Experimental Forest in New Hampshire, USA. Our results indicate that adverse impacts of reduced snowpack and increased soil freezing on the physiology of Acer saccharum (sugar maple), a dominant species across northern temperate forests, are accompanied by a 40 ± 3% reduction in aboveground woody biomass increment, averaged across the 6 years following the start of the experiment. Further, we find no indication of growth recovery 1 year after cessation of the experiment. Based on these findings, we integrate spatial modeling of snowpack depth with forest inventory data to develop a spatially explicit, regional‐scale assessment of the vulnerability of forest aboveground growth to projected declines in snowpack depth and increased soil frost. These analyses indicate that nearly 65% of sugar maple basal area in the northeastern United States resides in areas that typically experience insulating snowpack. However, under the RCP 4.5 and 8.5 emissions scenarios, we project a 49%–95% reduction in forest area experiencing insulating snowpack by the year 2099 in the northeastern United States, leaving large areas of northern forest vulnerable to these changes in winter climate, particularly along the northern edge of the region. Our study demonstrates that research focusing on growing season climate alone overestimates the stimulatory effect of warming temperatures on tree and forest growth in seasonally snow‐covered forests. 相似文献
15.
Roger Sanjek 《American anthropologist》2000,102(4):762-772
The United States is undergoing a "majority minority" transition, with the historic European-ancestry white majority projected to fall beneath 50% of the population in the second half of the current century. Elmhurst-Corona, a neighborhood in Queens, New York City, was 98% white in 1960 but by 1990 had become intensely multiracial, multiethnic, and multilingual, with neither African Americans, Asians, Latin Americans, nor the remaining whites constituting a majority of the local population. Based on ethnographic fieldwork between 1983 and 1996, in this article I trace the growth of cross-racial political interaction in Elmhurst-Corona, highlighting initial resistance by white residents, entry of newcomers into civic politics, innovation by female civic activists, and acceptance of shared local "quality of life" concerns as representation at the central political arena, the neighborhood's appointed community board, became more inclusive, [political anthropology, race, immigration, New York City, United States] 相似文献
16.
Harold White 《Bulletin of mathematical biology》1963,25(2):125-139
First a model for theb-wave of the electroretinogram is given. The essential part of the model is the diffusion into the rod-bipolar synapse of
a transmitter substance, followed by the induction of an inhibitor. Making use of this model, adaptation to an illumination
too weak to cause of significant decrease in the concentration of visual pigment is interpreted as due to a decreased effectiveness
of the rod impulse in exciting the bipolar cell. The disparity between threshold changes for very small test spots and for
relatively large spots is explained simply, without invoking any additional physiological mechanisms.
This research was supported in part by the United States Air Force through the Air Force Office of Scientific Research of
the Air Research Development Command under Contract No. AF(638)-414 and in part by the United States Public Health Service
Training Grant 2G-833. 相似文献
17.
BackgroundThe purpose of this study is to estimate and project the number of years of potential life lost (YPLL) among males who die of prostate cancer in the United States from 2004 through 2050 and compare the projections by race/ethnicity and age, accounting for demographic changes and population growth.MethodsWe applied the life expectancy method to estimate YPLL caused by deaths of prostate cancer and all cancers in men by using 1999–2004 national mortality data, 2008 census population demographic projections, and 2004 U.S. life tables. We performed sensitivity analyses by varying death rate and population projections, and examined increase in YPLL from population growth, changes in demographics, and death rates.ResultsThe number of YPLL caused by prostate cancer deaths was projected to increase by 226.1%, from 291,853 in 2004 to 951,753 in 2050. Hispanics were projected to have the fastest growth in YPLL (977.1% from 2004 to 2050) caused by prostate cancer, followed by non-Hispanic blacks (543.1%), and non-Hispanic others (269.7%). People aged 75 or older was projected to account for 62.0% of YPLL from prostate cancer in 2050 compared with 50.8% in 2004. Of the projected increase in YPLL caused by prostate cancer deaths by 2050, 9.8% were due to changes in demographic composition, 26.8% because of mortality change, and 63.4% because of population growth.ConclusionsYPLL due to prostate cancer deaths are projected to increase dramatically, and become a greater burden in the future. The projections highlight the importance of comprehensive cancer control and research on cancers including prostate cancer and racial/ethnic-specific estimates. 相似文献
18.
R G Spece J Marchalonis 《Cellular and molecular biology, including cyto-enzymology》2003,49(4):565-577
This article discusses the nature and purposes behind the three standards of proof commonly used in the United States. It summarizes the analytical constructs or standards of review courts commonly use to determine the constitutional validity of standards of proof (as well as other procedural protections) in physician disciplinary proceedings. It applies these constructs to the context of scientific misconduct and an illustrative case, and shows that sound policy and morals as well as procedural due process and equal protection provisions of the United States and some state constitutions require the use of the clear and convincing evidence standard of proof in scientific misconduct proceedings. That standard is necessary to protect scientists from misuse of scientific misconduct charges and proceedings, entailing, as they do, vast discretion in bureaucratic officials as well as staggering costs. The imminent rule making proceedings at the federal level will provide a special opportunity to right a wrong that long has been long visited upon academic scientists throughout the United States. 相似文献
19.
ABSTRACT: BACKGROUND: Since 2003, the United States National Institutes of Health (NIH) has sought to restructure the clinical research enterprise in the United States by promoting collaborative research partnerships between academically-based investigators and community-based physicians. By increasing community-based provider participation in research (CBPPR), the NIH seeks to advance the science of discovery by conducting research in clinical settings where most people get their care, and accelerate the translation of research results into everyday clinical practice. Although CBPPR is seen as a promising strategy for promoting the use of evidencebased clinical services in community practice settings, few empirical studies have examined the organizational factors that facilitate or hinder the implementation of CBPPR. The purpose of this study is to explore the organizational start-up and early implementation of CBPPR in community-based practice. METHODS: We used longitudinal, case study research methods and an organizational model of innovation implementation to theoretically guide our study. Our sample consisted of three community practice settings that recently joined the National Cancer Institute's (NCI) Community Clinical Oncology Program (CCOP) in the United States. Data were gathered through site visits, telephone interviews, and archival documents from January 2008 to May 2011. RESULTS: The organizational model for innovation implementation was useful in identifying and investigating the organizational factors influencing start-up and early implementation of CBPPR in CCOP organizations. In general, the three CCOP organizations varied in the extent to which they achieved consistency in CBPPR over time and across physicians. All three CCOP organizations demonstrated mixed levels of organizational readiness for change. Hospital management support and resource availability were limited across CCOP organizations early on, although they improved in one CCOP organization. As a result of weak IPPs, all three CCOPs created a weak implementation climate. Patient accrual became concentrated over time among those groups of physicians for whom CBPPR exhibited a strong innovation-values fit. Several external factors influenced innovation use, complicating and enriching our intra-organizational model of innovation implementation. CONCLUSION: Our results contribute to the limited body of research on the implementation of CBPPR. They inform policy discussions about increasing and sustaining community clinician involvement in clinical research and expand on theory about organizational determinants of implementation effectiveness. 相似文献
20.
Helmut Haberl Helga Weisz Christof Amann Alberte Bondeau Nina Eisenmenger Karl‐Heinz Erb Marina Fischer‐Kowalski Fridolin Krausmann 《Journal of Industrial Ecology》2006,10(4):151-171
This article presents an assessment of energy inputs of the European Union (the 15 countries before the 2004 enlargement, abbreviated EU‐15) for the period 1970–2001 and the United States for 1980–2000. The data are based on an energy flow analysis (EFA) that evaluates socioeconomic energy flows in a way that is conceptually consistent with current materials flow analysis (MFA) methods. EFA allows assessment of the total amount of energy required by a national economy; it yields measures of the size of economic systems in biophysical units. In contrast to conventional energy balances, which only include technically used energy, EFA also accounts for socioeconomic inputs of biomass; that is, it also considers food, feed, wood and other materials of biological origin. The energy flow accounts presented in this article do not include embodied energy. Energy flow analyses are relevant for comparisons across modes of subsistence (e.g., agrarian and industrial society) and also to detect interrelations between energy utilization and land use. In the EU‐15, domestic energy consumption (DEC = apparent consumption = domestic extraction plus import minus export) grew from 60 exajoules per year (1 EJ = 1018 J) in 1970 to 79 EJ/yr in 2001, thus exceeding its territory's net primary production (NPP, a measure of the energy throughput of ecosystems). In the United States, DEC increased from 102 EJ/yr in 1980 to 125 EJ/yr in 2000 and was thus slightly smaller than its NPP. Taken together, the EU‐15 and the United States accounted for about 38% of global technical energy use, 31% of humanity's energetic metabolism, but only 10% of global terrestrial NPP and 11% of world population in the early 1990s. Per capita DEC of the United States is more than twice that of the EU‐15. Calculated according to EFA methods, energy input in the EU and the United States was between one‐fifth and one‐third above the corresponding value reported in conventional energy balances. The article discusses implications of these results for sustainability, as well as future research needs. 相似文献