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61.
The value of natural history collections for conservation science research is increasingly recognized, despite their well-documented limitations in terms of taxonomic, geographic, and temporal coverage. Specimen-based analyses are particularly important for tropical plant groups for which field observations are scarce and potentially unreliable due to high levels of diversity-amplifying identification challenges. Specimen databases curated by specialists are rich sources of authoritatively identified, georeferenced occurrence data, and such data are urgently needed for large genera. We compared entries in a monographic database for the large Neotropical genus Myrcia in 2007 and 2017. We classified and quantified differences in specimen records over this decade and determined the potential impact of these changes on conservation assessments. We distinguished misidentifications from changes due to taxonomic remodeling and considered the effects of adding specimens and georeferences. We calculated the potential impact of each change on estimates of extent of occurrence (EOO), the most frequently used metric in extinction-risk assessments of tropical plants. We examined whether particular specimen changes were associated with species for which changes in EOO over the decade were large enough to change their conservation category. Corrections to specimens previously misidentified or lacking georeferences were overrepresented in such species, whereas changes associated with taxonomic remodeling (lumping and splitting) were underrepresented. Among species present in both years, transitions to less threatened status outnumbered those to more threatened (8% vs 3%, respectively). Species previously deemed data deficient transitioned to threatened status more often than to not threatened (10% vs 7%, respectively). Conservation scientists risk reaching unreliable conclusions if they use specimen databases that are not actively curated to reflect changing knowledge.  相似文献   
62.
In spring 2011, an unprecedented flood hit the complex eastern United States (U.S.)–Canada transboundary Lake Champlain–Richelieu River (LCRR) Basin, destructing properties and inducing negative impacts on agriculture and fish habitats. The damages, covered by the Governments of Canada and the U.S., were estimated to C$90M. This natural disaster motivated the study of mitigation measures to prevent such disasters from reoccurring. When evaluating flood risks, long‐term evolving climate change should be taken into account to adopt mitigation measures that will remain relevant in the future. To assess the impacts of climate change on flood risks of the LCRR basin, three bias‐corrected multi‐resolution ensembles of climate projections for two greenhouse gas concentration scenarios were used to force a state‐of‐the‐art, high‐resolution, distributed hydrological model. The analysis of the hydrological simulations indicates that the 20‐year return period flood (corresponding to a medium flood) should decrease between 8% and 35% for the end of the 21st Century (2070–2099) time horizon and for the high‐emission scenario representative concentration pathway (RCP) 8.5. The reduction in flood risks is explained by a decrease in snow accumulation and an increase in evapotranspiration expected with the future warming of the region. Nevertheless, due to the large climate inter‐annual variability, short‐term flood probabilities should remain similar to those experienced in the recent past.  相似文献   
63.
Significant amounts of volatile organic compounds and greenhouse gases are generated from wastewater lagoons and tailings ponds in Alberta, Canada. Accurate measurements of these air pollutants and greenhouse gases are needed to support management and regulatory decisions. A mobile platform was developed to measure air emissions from tailings pond in the oil sands region of Alberta. The mobile platform was tested in 2015 in a municipal wastewater treatment lagoon. With a flux chamber and a CO2/CH4 sensor on board, the mobile platform was able to measure CO2 and CH4 emissions over two days at two different locations in the pond. Flux emission rates of CO2 and CH4 that were measured over the study period suggest the presence of aerobic and anaerobic zones in the wastewater treatment lagoon. The study demonstrated the capabilities of the mobile platform in measuring fugitive air emissions and identified the potential for the applications in air and water quality monitoring programs.

Implications: The Mobile Platform demonstrated in this study has the ability to measure greenhouse gas (GHG) emissions from fugitive sources such as municipal wastewater lagoons. This technology can be used to measure emission fluxes from tailings ponds with better detection of spatial and temporal variations of fugitive emissions. Additional air and water sampling equipment could be added to the mobile platform for a broad range of air and water quality studies in the oil sands region of Alberta.  相似文献   

64.
The amount of extruded polystyrene (XPS) waste has increased in recent years due to the increase of its use in the thermal insulation of buildings, transport vehicles, and refrigerators, among others. Dissolution with suitable solvents to achieve a volume reduction of more than 100 times without degradation of polymer chains is one of the cheapest and most efficient methods of recycling XPS. Several environmentally friendly solvents have been tested as dissolution agents for XPS volume reduction; the action of these solvents does not produce any degradation of polymer chains. The solubility of the polymer in such solvents at different temperatures was investigated. The solvent can be easily recycled by distillation, obtaining a high-quality recycled polymer. Chemical Feedstock Recycling & Other Innovative Recycling Techniques 6  相似文献   
65.
This paper examines and compares the management practices and regulatory approaches used by the Mid-Atlantic States of Delaware, Maryland, New Jersey, and Pennsylvania for improving the quality of storm-water runoff. Such practices range from simple extended detention criteria in Pennsylvania through the BMP credit system used by Maryland, to the latest "green technology" methods promoted in Delaware and the recharge, quality and peak reduction approaches of New Jersey. All practices are designed to meet EPA requirements for total suspended solids (TSS) removal, but verification of performance is not required. More sophisticated methods of evaluating TSS removal that can be used for engineering design purposes are needed.  相似文献   
66.
Assessing species’ extinction risk is vital to setting conservation priorities. However, assessment endeavors, such as those used to produce the IUCN Red List of Threatened Species, have significant gaps in taxonomic coverage. Automated assessment (AA) methods are gaining popularity to fill these gaps. Choices made in developing, using, and reporting results of AA methods could hinder their successful adoption or lead to poor allocation of conservation resources. We explored how choice of data cleaning type and level, taxonomic group, training sample, and automation method affect performance of threat status predictions for plant species. We used occurrences from the Global Biodiversity Information Facility (GBIF) to generate assessments for species in 3 taxonomic groups based on 6 different occurrence-based AA methods. We measured each method's performance and coverage following increasingly stringent occurrence cleaning. Automatically cleaned data from GBIF performed comparably to occurrence records cleaned manually by experts. However, all types of data cleaning limited the coverage of AAs. Overall, machine-learning-based methods performed well across taxa, even with minimal data cleaning. Results suggest a machine-learning-based method applied to minimally cleaned data offers the best compromise between performance and species coverage. However, optimal data cleaning, training sample, and automation methods depend on the study group, intended applications, and expertise.  相似文献   
67.

Background, aims, and scope

Formaldehyde (FA) is a harmful chemical, which is classified as carcinogenic to humans (Group 1) by the International Agency for Research on Cancer. Solutions of FA that are used to preserve cadavers in research and education morphological institutes represent a risk to occupational health of professionals and students. During the dissection of cadavers in the anatomy laboratories, FA vapors are emitted, resulting in the exposure of students and their instructors to elevated levels of FA. The World Health Organization recommends an air quality guideline value of 0.1 mg m?3 for exposure to FA. The limit of occupational exposure adopted by the Brazilian legislation (2.3 mg m?3) is markedly higher than those adopted by institutions of other countries around the world. The purpose of this study was to determine the levels of personal exposure and the area concentration of FA in the morphology department of the Federal Fluminense University, Brazil, and investigate and compare the relationship between them.

Methods

Four rooms distributed in the three floors of the Morphology Department were evaluated: the embalming laboratory, the anatomy laboratories, the corridor of the teachers?? rooms, and the entrance hall. Thirty-six samples in total were collected in the second semester of 2010 and first semester of 2011. The air sampling and FA analysis were performed according to the EPA TO-11A Protocol, using a diffusive sampling device for carbonyl compounds. Personal samples were collected from monitors using a sampling device pinned on each person??s lapel. The samples were analyzed using rapid resolution liquid chromatography with UV-DAD detection at 360 nm.

Results and discussion

The concentrations of FA ranged from 0.20 and 0.18 mg m?3 in the corridor between the teachers?? rooms, 0.03 to 0.37 mg m?3 in the entrance hall, 0.22 to 2.07 mg m?3 in the anatomy laboratory, 2.21 to 2.52 mg m?3, in the embalming room. The levels found in the corridor between the teachers?? rooms and in the entrance hall were lower than in other compartments because of their large distances to the sources of FA and better ventilation. The other rooms presented higher levels of FA because of the activities carried there (embalming and dissection procedures). Even in the rooms that showed the lowest levels of FA, the values found were higher than those established by all international guideline limits, except the Brazilian legislation limit, although, the concentration level in the embalming room was even greater than the Brazilian guideline. These concentrations are 100?C1,000-fold higher than those reported in an FA outdoor study. The exposure levels of monitors and students ranged from 1.89 to 4.82 mg m?3, indicating that current practices at the Morphology Department at the university would represent a health risk. The simultaneous monitoring of area concentrations and personal exposure showed that the characteristics of classes and of cadavers?? parts, the number of students in the room and even the activities of the monitors influence the FA concentrations.

Conclusion

This study revealed that the concentration of FA was low in the ventilated areas of the Morphology Department, and that the personal exposure when the person was close to the cadavers during the dissection procedure was higher than the mean FA concentration. This should be considered in the risk assessment of FA during these activities without effective protection equipment. It is suggested that the Brazilian legislation of exposure to formaldehyde requires an urgent update considering international legislation.  相似文献   
68.
The term “wet scrubber” or simply “scrubber,” for the purpose of this report, is intended to include any device using liquid to effect the removal of solid or liquid particles which are entrained in process air or gas streams. This guide is intended to provide information required for the selection and performance evaluation of all types of scrubbers installed for the primary purpose of removing such particulates from any process gas stream. It is not intended to cover scrubbers for the collection of gaseous and/or vapor constituents which involve gas absorption mechanisms.  相似文献   
69.
Accumulating and maintaining sufficient energy reserves is critical for winter survival of birds. Because high fat levels are assumed to be associated with higher risk of predation, birds have been hypothesized to regulate their body mass as a trade-off between risk of starvation and risk of predation. Theoretical models of energy management in birds typically assume that predation risk is constant throughout the day. However, this important assumption has little empirical support, and there is some evidence suggesting that it might not always be correct and that predation risk may vary during the day. Because predation risk is a critical component of the predation-starvation trade-off, any change in its value through the day might have a profound effect on birds' optimal daily tactics of energy accumulation. We used a dynamic optimization model to investigate how changes in predation risk might affect birds' energy management decisions. Daily patterns of fat accumulation and feeding activity were predicted to change with predation risk in a manner consistent with previous models (lower mass gain and less feeding when predation risk is high). Our more counterintuitive results concern daily patterns of food caching and cache retrieval. When predation risk was assumed to peak at midday, birds were predicted to cache primarily in the afternoon and not in the morning even though predation risk was identical in the morning and afternoon. With other temporal patterns of predation risk, caching intensity was highest when predation risk was lowest. Surprisingly, the daily pattern of cache retrieval was predicted to be unaffected by daily patterns of predation risk: birds were always predicted to retrieve their caches primarily during the late afternoon with a small peak in the morning. Highest mortality was predicted with predation risk decreasing from morning to evening whereas lowest mortality was predicted with predation risk increasing from morning to evening. Our model helps explain large variations in observed daily patterns of energy management in birds and provides testable predictions that could help us understand the daily dynamics of predation risk and how birds should respond to it.  相似文献   
70.
Under pressure from public opinion, the attitude of companies toward environmental issues has changed considerably since the 1970s. Over the past decades, there have been three distinct generations of environmental strategies and indicators. Now, at the beginning of a new century, we can start to see the contours of the fourth generation of environmental strategies and indicators—a generation that eventually will change the rules of the business game. © 2001 John Wiley & Sons, Inc.  相似文献   
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