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21.
Globally, urban growth will add 1.5 billion people to cities by 2030, making the difficult task of urban water provisions
even more challenging. In this article, we develop a conceptual framework of urban water provision as composed of three axes:
water availability, water quality, and water delivery. For each axis, we calculate quantitative proxy measures for all cities
with more than 50,000 residents, and then briefly discuss the strategies cities are using in response if they are deficient
on one of the axes. We show that 523 million people are in cities where water availability may be an issue, 890 million people
are in cities where water quality may be an issue, and 1.3 billion people are in cities where water delivery may be an issue.
Tapping into groundwater is a widespread response, regardless of the management challenge, with many cities unsustainably
using this resource. The strategies used by cities deficient on the water delivery axis are different than for cities deficient
on the water quantity or water quality axis, as lack of financial resources pushes cities toward a different and potentially
less effective set of strategies. 相似文献
22.
23.
The rise of dual‐earner couples challenges traditional gender stereotypes of women as “caregivers” and men as “breadwinners” and significantly impacts the ways in which partners define their roles as family members. The way in which individuals construe their family identities has implications not only for the decisions they make at home but also decisions in the workplace. In this paper, we propose an updated understanding of the different ways in which men and women can construe their family identity—specifically, in terms of care and/or career. Based upon this nuanced understanding of family identity, we outline five dual‐earner couple types—traditional, non‐traditional, family first, outsourced, and egalitarian—that stem from distinct combinations of partners' family identities. We also outline an agenda for theory and research that challenges scholars to further explore our proposed construals of family identity, work–family decisions at the couple level of analysis, and the interplay between family identity and social context. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
24.
Lowenthal DH Kumar N Hand J Day D Kreidenweis S Collett J Lee T Ashbaugh L 《Journal of the Air & Waste Management Association (1995)》2003,53(10):1273-1279
The hygroscopic properties of the organic fraction of aerosols are poorly understood. The ability of organic aerosols to absorb water as a function of relative humidity (RH) was examined using data collected during the 1999 Big Bend Regional Aerosol and Visibility Observational Study (BRAVO). (On average, organics accounted for 22% of fine particulate matter with an aerodynamic diameter less than 2.5 microm (PM2.5) mass). Hourly RH exceeded 80% only 3.5% of the time and averaged 44%. BRAVO aerosol chemical composition and dry particle size distributions were used to estimate PM2.5 light scattering (Bsp) at low and high ambient RH. Liquid water growth associated with inorganic species was sufficient to account for measured Bsp for RH between 70 and 95%. 相似文献
25.
Alastair W. Robertson ‡ Dave Kelly † Jenny J. Ladley † and Ashley D. Sparrow† 《Conservation biology》1999,13(3):499-508
Abstract: The endemic mistletoes Peraxilla colensoi and P. tetrapetala (Loranthaceae) have declined considerably in New Zealand since 1840, reputedly because of introduced herbivores but coincident with a major decline in native bird densities. We show that at two South Island sites ( Craigieburn and Ohau) there are too few bird pollinators visiting the flowers to allow full fruit set. We studied pollination rates in P. colensoi at Wakefield and P. tetrapetala at Craigieburn over four flowering seasons and P. tetrapetala in one season at Ohau. Supplemental hand pollination increased fruit production 1.25–5.3 times at Craigieburn and Ohau but not at Wakefield. Excluding birds by covering mistletoes with mesh bags decreased fruit set significantly at Wakefield but had little effect at Craigieburn and Ohau. Bellbirds ( Anthornis melanura ) and Tuis ( Prosthemadera novaeseelandiae ) visited flowers significantly more often at Wakefield than at Craigieburn. A lack of pollen tubes in the style, not self-incompatibility or resource shortage, caused the low fruit production in unmanipulated flowers at Craigieburn. Thus, at the two P. tetrapetala sites (Craigieburn and Ohau) fruit set was chronically pollen limited, whereas P. colensoi at Wakefield was not pollen-limited. Data from other Peraxilla sites also suggest pollination failure. Our study suggests that the conservation of Peraxilla species will require maintenance of native bird populations. Tuis and Bellbirds are important pollinators and dispersers of many other New Zealand plants, and the breakdown of such mutualistic relationships may have widespread consequences. 相似文献
26.
Summary. The among-leaves allocation of DIBOA, a hydroxamic acid associated with plant resistance, in the shoot of rye (Secale cereale) was evaluated over the vegetative development of the plant. The appropriateness of using the concentration of secondary
metabolites, DIBOA in this case, as the parameter to evaluate defense allocation in plants is discussed. Both biological and
statistical arguments are put forward to suggest that allocation of chemical defenses should refer to absolute content and
not to concentration. Results showed that leaf age was significantly linked to leaf concentration of DIBOA, young leaves having
higher concentrations. In contrast, leaf content of DIBOA, our proposed currency of allocation, was not significantly higher
in younger leaves. Furthermore, a regression analysis showed that the DIBOA content of leaves was better explained by the
leaf relative biomass (proportion of shoot biomass) than by leaf biomass itself. It is suggested that, rather than leaf age,
leaf relative biomass is the major factor determining DIBOA allocation in rye shoots. It is proposed that studies addressing
within-plant defense allocation should use chemical defense content as the currency, emphasizing the major factors driving
this process and its underlying mechanisms. Likewise, it is proposed that studies aiming at characterizing optimal patterns
of plant defense should use chemical defense concentration as the currency, and be accompanied by evaluations of the actual
resistance against herbivores of the plant parts analyzed, together with the effect on plant fitness.
Received 19 February 1999; accepted 28 April 1999. 相似文献
27.
Ong Jenny Mahmood Noor Zalina Musa Siti Nurmaya 《Journal of Material Cycles and Waste Management》2021,23(3):1258-1269
Journal of Material Cycles and Waste Management - Malaysia is a developing country, and its economic growth has caused the increase in the generation of industrial waste in terms of its volume. The... 相似文献
28.
Impacts of pollution controls on air quality in Beijing during the 2008 Olympic Games 总被引:1,自引:0,他引:1
Shen J Tang A Liu X Kopsch J Fangmeier A Goulding K Zhang F 《Journal of environmental quality》2011,40(1):37-45
Air pollution has become one of the main environmental concerns in China since the 1980s due to China's rapid economic growth and resultant pollution. However, it is difficult to directly evaluate the anthropogenic contribution to air pollution in China. The 2008 Olympic Games in Beijing provided a unique opportunity for testing the contribution of anthropogenic pollution because of the clean-up controls on air quality in Beijing enforced over the period of the Games. In this case study, we monitored the concentrations of major air pollutants before, during, and after the Olympics at a suburban site in Beijing. Atmospheric concentrations of PM10, PM2.5, NH3, NO2, SO2, and the particulate ions NH4+, NO3-, SO4(2-) Ca2+, Mg2+, and K+ all decreased during the Olympic period because of strict emission controls, compared with the same period from 2005 to 2007. For example, the average PM10 concentration (61 microg m(-3)) during the Olympics was only 37% of that (166 microg m(-3)) in the same month (August) from 2005 to 2007. However, just 1 mo and 1 yr after the Games had ended, mean concentrations of these pollutants had increased significantly again. This rapid "recovery' of air pollutant concentrations after the Olympics suggests that China needs to implement long-lasting decreases in its air pollution in Beijing and other major cities. 相似文献
29.
Arp HP Møskeland T Andersson PL Nyholm JR 《Journal of environmental monitoring : JEM》2011,13(3):505-513
The brominated flame retardants (BFRs), pentabromotoluene (PBT), pentabromoethylbenzene (PBEB) and hexabromobenzene (HBB), exhibit physical-chemical properties similar to other persistent organic pollutants, and have been in use as flame retardants for several decades. Data on these BFRs in diverse environmental samples can be found in studies from the 1970s and 1980s, as well as in recent years, though very little in the years in between. Due to a lack of data, the cause for the apparent re-emergence of these BFRs in recent studies is unclear, and could reflect changes in production volumes, accumulation of transformation products from BFR precursors, improved analytical techniques or simply a re-emergence in concern. Very little data are available on their environmentally relevant partitioning properties, which could help to explain the occurrence and fate of these BFRs. In this study we analysed for the presence of HBB, PBT, and PBEB in diverse environmental samples from potential Norwegian BFR source zones. Additionally, environmental partitioning properties of these BFRs as well as brominated benzenes were estimated and validated using experimental data for brominated benzenes. Of the three BFRs, HBB was identified in detectable quantities at most source zones, PBEB only near a metal recycling factory, and PBT only in a few additional locations from where PBEB was detected. Data from this study show that HBB is likely widely distributed, as verified both by chemical analysis and estimated properties. Measured HBB levels in wastewater treatment plants indicate that the treatment practices used in the study locations are not effective at lowering HBB levels, perhaps due to association with low density suspended solids (e.g. microplastics). 相似文献
30.
Peter E. Schmid und Jenny M. Schmid-Araya 《Umweltwissenschaften und Schadstoff-Forschung》2001,13(5):255-257
Ohne Zusammenfassung 相似文献