In the first tier risk assessment (RA) of pesticides, risk for aquatic communities is estimated by using results from standard laboratory tests with algae, daphnids and fish for single pesticides such as herbicides, fungicides, and insecticides. However, fungi as key organisms for nutrient cycling in ecosystems as well as multiple pesticide applications are not considered in the RA. In this study, the effects of multiple low pesticide pulses using regulatory acceptable concentrations (RACs) on the dynamics of non-target aquatic fungi were investigated in a study using pond mesocosm. For that, fungi colonizing black alder (Alnus glutinosa) leaves were exposed to multiple, low pulses of 11 different pesticides over a period of 60 days using a real farmer''s pesticide application protocol for apple cropping. Four pond mesocosms served as treatments and 4 as controls. The composition of fungal communities colonizing the litter material was analyzed using a molecular fingerprinting approach based on the terminal Restriction Fragment Length Polymorphism (t-RFLP) of the fungal Internal Transcribed Spacer (ITS) region of the ribonucleic acid (RNA) gene(s). Our data indicated a clear fluctuation of fungal communities based on the degree of leaf litter degradation. However significant effects of the applied spraying sequence were not observed. Consequently also degradation rates of the litter material were not affected by the treatments. Our results indicate that the nutrient rich environment of the leaf litter material gave fungal communities the possibility to express genes that induce tolerance against the applied pesticides. Thus our data may not be transferred to other fresh water habitats with lower nutrient availability. 相似文献
Objective: There are little objective data on whether drivers with lane departure warning and forward collision warning systems actually use them, but self-report data indicate that lane departure warning may be used less and viewed less favorably than forward collision warning. The current study assessed whether the systems were turned on when drivers brought their vehicles to dealership service stations and whether the observational protocol is a feasible method for collecting similar data on various manufacturers' systems.
Methods: Observations of 2013–2015 Honda Accords, 2014–2015 Odysseys, and 2015 CR-Vs occurred at 2 U.S. Honda dealerships for approximately 4 weeks during Summer 2015.
Results: Of the 265 vehicles observed to have the 2 systems, 87 (32.8%) had lane departure warning turned on. Accords were associated with a 66% increase in the likelihood that lane departure warning was turned on compared with Odysseys, but the rate was still only about 40% in Accords. In contrast, forward collision warning was turned on in all but one of the observed vehicles.
Conclusions: Observations found that the activation rate was much higher for forward collision warning than lane departure warning. The observation method worked well and appears feasible for extending to other manufacturers. 相似文献
Food sovereignty asserts the right of peoples to define and organize their own agricultural and food systems so as to meet local needs and so as to secure access to land, water and seed. A commitment to gender equity has been embedded in the food sovereignty concept from its earliest articulations. Some might wonder why gender justice should figure so prominently in a food movement. In this paper I review and augment the arguments for making gender equity a central component of food sovereignty. The most common argument is: if women constitute the majority of the world’s food producers, then agricultural policy is a women’s issue. And insofar as patriarchal social relations continue to dominate the globe, then changing agricultural policies will require explicit attention to gender injustice. I suggest that this is a good argument, but that an ecological feminist perspective can provide additional theoretical reasons for maintaining the centrality of gender justice in food sovereignty discourse. Moreover, ecological feminism can provide a robust theoretical framework that coheres a concept and movement with a wide set of concerns. My critique positions food sovereignty’s call to social justice as embedded in a truly radical re-thinking of dominant conceptual frameworks, and re-envisioning of political and ethical relations. 相似文献
This article summarizes the primary outcomes of an interdisciplinary workshop in 2010, sponsored by the U.S. National Science Foundation, focused on developing key questions and integrative themes for advancing the science of human–landscape systems. The workshop was a response to a grand challenge identified recently by the U.S. National Research Council (2010a)—“How will Earth’s surface evolve in the “Anthropocene?”—suggesting that new theories and methodological approaches are needed to tackle increasingly complex human–landscape interactions in the new era. A new science of human–landscape systems recognizes the interdependence of hydro-geomorphological, ecological, and human processes and functions. Advances within a range of disciplines spanning the physical, biological, and social sciences are therefore needed to contribute toward interdisciplinary research that lies at the heart of the science. Four integrative research themes were identified—thresholds/tipping points, time scales and time lags, spatial scales and boundaries, and feedback loops—serving as potential focal points around which theory can be built for human–landscape systems. Implementing the integrative themes requires that the research communities: (1) establish common metrics to describe and quantify human, biological, and geomorphological systems; (2) develop new ways to integrate diverse data and methods; and (3) focus on synthesis, generalization, and meta-analyses, as individual case studies continue to accumulate. Challenges to meeting these needs center on effective communication and collaboration across diverse disciplines spanning the natural and social scientific divide. Creating venues and mechanisms for sustained focused interdisciplinary collaborations, such as synthesis centers, becomes extraordinarily important for advancing the science. 相似文献
The mean vigilance of animals in a group often decreases as their group size increases, yet nothing is known about whether
there is individual variability in this relationship in species that change group sizes frequently, such as those that exhibit
fission–fusion social systems. We investigated variability in the relationship between group size and vigilance in the eastern
grey kangaroo (Macropus giganteus) by testing whether all individuals showed decreased vigilance with increased group size, as has been commonly assumed. We
carried out both behavioural observations of entire groups of kangaroos and focal observations of individually recognised
wild female kangaroos. As in other studies, we found a collective group-size effect on vigilance; however, individuals varied
in their vigilance patterns. The majority (57%) of the identified individual kangaroos did not show significant group-size
effects for any of the recorded measures of vigilance. The females that did not show a negative group-size effect were, on
average, more vigilant than those females that did show a group-size effect, but this difference was not significant. We propose
that some females exhibit higher levels of social vigilance than others, and that this social vigilance increases with group
size, cancelling out any group-size effect on anti-predator vigilance for those females. Our results therefore suggest that
only some prey individuals may gain anti-predator benefits by reducing their time spent scanning when in larger groups. The
large amount of variation that we found in the vigilance behaviour of individual kangaroos highlights the importance of collecting
and analysing vigilance data at the individual level, which requires individual recognition. 相似文献