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101.
102.
Asulam is often applied from the air to control bracken. This herbicide affects other ferns and spray drift could affect their survival. This paper discusses the use of bioassays to assess drift (a) spatially around a single bracken patch, (b) downwind from sprayed areas, and (c) spatially in undulating terrain and with different vegetation cover types. The aims were to develop policies to protect sensitive habitats. It is suggested that “no-spray” buffer zones in excess of 160–180 m are needed to minimise risk. Protection of rare ferns from overstorey vegetation or from steep slopes did not occur. Although less drift was found upwind there was significant damage at the end of the helicopter runs because of errors in switching the sprayer on and off. 相似文献
103.
Adrienne I. Greve Jim C. Loftis Juliane B. Brown Rob R. Buirgy Ben Alexander 《Journal of the American Water Resources Association》2003,39(6):1409-1418
ABSTRACT: In 1996, the Big Thompson Watershed Forum (BTWF) was formed “to assess and protect the quality of water” in the Big Thompson Watershed in northern Colorado. However, until 1999, water quality monitoring in the watershed was performed by many state, local, and federal agencies with no coordination among programs and with few efforts toward efficiency, data comparability, or information exchange. To better meet the needs of its stakeholders, the BTWF since 1999 has been actively pursuing the design and implementation of a cooperative water quality monitoring program. The program design involved consensus building among the funding participants, primarily drinking water providers. The final design included 38 parameters to be sampled 15 times per year at 24 stream and canal locations plus two reservoirs. Although the collaborative consensus based approach has been successful for the BTWF, this approach has its drawbacks; most notable among these are the time and labor this approach requires. Also, the BTWF struggled with achieving equal representation of all interests, since those agencies that provided funding had the greatest voice in the final product. While a collaborative approach may not always be best for monitoring program design, it should be appropriate for many watershed organizations that face the common problem of severe financial constraints. 相似文献
104.
Rob C. De Loë Danielle K. Lukovich 《Journal of Environmental Planning and Management》2004,47(4):517-539
Through their powers to regulate land use and their responsibilities for public water supply, local governments are critical players in groundwater protection. Unfortunately, the demands of groundwater protection are high, and many local governments do not have the ability or capacity to develop and implement appropriate management strategies. This paper analyzes groundwater protection experiences on Long Island, New York, a place where groundwater dependence is high, and threats to groundwater are serious. Long Island's experiences highlight the need to approach capacity building for groundwater protection broadly, concentrating on factors such as political commitment and citizen support; enhancement of local technical competency through linkages and support from state and federal governments; and strengthening of institutional arrangements at all levels. 相似文献
105.
This paper uses a cultural model approach to interpret and analyse the impact of an interactive computer simulation tool (GB-Quest) on the possibility of fostering dialogue about sustainability in southwestern British Columbia, Canada. We define cultural models theory, compare cultural models to mental models and illustrate some basic features of cultural models. We then describe the research process in which participants engaged in conversation, guided and facilitated by GB-Quest, about sustainability. Findings suggest that the use of cultural models frameworks reinforces participants' understanding of sustainability. In reflecting on their prior models of sustainability, we argue that study participants can elucidate how cognitive conceptual resources reflect publicly shared knowledge (Turner, 2004). 相似文献
106.
Ibrahim Hafeezur Rehman Abhishek Kar Rob Raven Dilip Singh Jitendra Tiwari Rakesh Jha Pramod Kumar Sinha Asim Mirza 《Environmental Science & Policy》2010,13(4):303-311
In most developing countries, at the household level, traditional burning of biomass or use of inefficient technologies for domestic applications like lighting is common, triggering concerns related to fuel or technology switching. The paper focuses on opportunities to promote cleaner energy options through development of value chains delivering improved energy efficiency and access in developing countries. We discuss the example of Uttam Urja, a field project involving the dissemination of photovoltaic lighting technologies in rural areas of India. We focus on the challenges of introducing radical innovations into the residential energy sector in developing countries. For the purpose of this paper the Uttam Urja project is conceptualized as an ‘experiment’ and analysed using the Strategic Niche Management (SNM) framework. The paper emphasizes that to effect socio-technical transitions to clean energy options on the ground, it is desirable to focus on technology customization and innovative financing to cater to the needs and concerns of end users. 相似文献
107.
van Ginneken V Ballieux B Antonissen E van der Linden R Gluvers A van den Thillart G 《Die Naturwissenschaften》2007,94(2):128-133
In birds and mammals, the thyroid gland secretes the iodothyronine hormones of which tetraiodothyronine (T4) is less active
than triiodothyronine (T3). The action of T3 and T4 is calorigenic and is involved in the control of metabolic rate. Across
all vertebrates, thyroid hormones also play a major role in differentiation, development and growth. Although the fish thyroidal
system has been researched extensively, its role in thermogenesis is unclear. In this study, we measured overall heat production
to an accuracy of 0.1 mW by direct calorimetry in a free-moving European eel (Anguilla anguilla L.) with different thyroid status. Hyperthyroidism was induced by injection of T3 and T4, and hypothyroidism was induced
with phenylthiourea. The results show for the first time at the organismal level, using direct calorimetry, that neither overall
heat production nor overall oxygen consumption in eels is affected by hyperthyroidism. Therefore, we conclude that the thermogenic
metabolism-stimulating effect of thyroid hormones (TH) is not present with a cold-blooded fish species like the European eel.
This supports the concept that TH does not stimulate thermogenesis in poikilothermic species. 相似文献
108.
109.
Philip J. Platts Colin J. McClean Jon C. Lovett Rob Marchant 《Ecological modelling》2008,218(1-2):121-134
The Eastern Arc Mountains (EAMs) of Tanzania and Kenya support some of the most ancient tropical rainforest on Earth. The forests are a global priority for biodiversity conservation and provide vital resources to the Tanzanian population. Here, we make a first attempt to predict the spatial distribution of 40 EAM tree species, using generalised additive models, plot data and environmental predictor maps at sub 1 km resolution. The results of three modelling experiments are presented, investigating predictions obtained by (1) two different procedures for the stepwise selection of predictors, (2) down-weighting absence data, and (3) incorporating an autocovariate term to describe fine-scale spatial aggregation. In response to recent concerns regarding the extrapolation of model predictions beyond the restricted environmental range of training data, we also demonstrate a novel graphical tool for quantifying envelope uncertainty in restricted range niche-based models (envelope uncertainty maps). We find that even for species with very few documented occurrences useful estimates of distribution can be achieved. Initiating selection with a null model is found to be useful for explanatory purposes, while beginning with a full predictor set can over-fit the data. We show that a simple multimodel average of these two best-model predictions yields a superior compromise between generality and precision (parsimony). Down-weighting absences shifts the balance of errors in favour of higher sensitivity, reducing the number of serious mistakes (i.e., falsely predicted absences); however, response functions are more complex, exacerbating uncertainty in larger models. Spatial autocovariates help describe fine-scale patterns of occurrence and significantly improve explained deviance, though if important environmental constraints are omitted then model stability and explanatory power can be compromised. We conclude that the best modelling practice is contingent both on the intentions of the analyst (explanation or prediction) and on the quality of distribution data; generalised additive models have potential to provide valuable information for conservation in the EAMs, but methods must be carefully considered, particularly if occurrence data are scarce. Full results and details of all species models are supplied in an online Appendix. 相似文献
110.
Behavioural research on domestic pigs has included parent–offspring conflict, sibling competition, and the use of signals
which influence resource allocation. In this paper, we review key sow–piglet behavioural studies and discuss their relevance
to resource allocation theory. Sibling competition begins in the uterus and continues after birth, as piglets compete directly
for access to the sow’s teats. This competition is made more severe by a unique dentition, which newborn piglets use to lacerate
the faces of siblings during teat disputes. Competition often leads to the death of some littermates, especially those of
low birth weight. Piglets also compete indirectly for milk, apparently by stimulating milk production at the teats that they
habitually use at the expense of milk production by other teats. The complex nursing behavior of the sow appears designed
to prevent the more vigorous piglets from monopolizing the milk. Sows give vocal signals which both attract piglets to suckle
and synchronize their behavior during nursing episodes. Piglets give loud vocal signals when separated from the sow; calls
which vary in intensity and appear to be honest signals of need. Udder massage by piglets may also serve as an honest signal
of need. Parent–offspring conflict has been demonstrated experimentally in pigs. Specifically, when given the opportunity
to control contact with their piglets, sows nurse less frequently, provide less milk, and lose less weight during lactation
than sows that cannot control their level of contact. Because of this interesting natural history and because they are so
amenable to experimentation, domestic pigs provide a rich system for testing ideas drawn from resource allocation theory.
This contribution is part of the special issue “Sibling competition and cooperation in mammals” (guest editors: Robyn Hudson
and Fritz Trillmich). 相似文献