1,204 research outputs found
Geophysical surveys near Strontian, Highland Region
Reconnaissance VLF-EM and magnetic surveys have bean carried out over Ba-
Pb-Zn prospects in an area near Strontian in the Highland Region of Scotland.
Rather than attempting to detect the economic minerals directly, which is
unlikely to be practicable by geophysical methods, the trials concentrated on
exploration for the crush zones and associated Permo-Carboniferous basic dykes
which act as hosts to mineralisation. The results are encouraging, with the
VLF-EM method proving effective in delineating crush zones while magnetic
traverses detected the basic dykes. To the east of Bellsgrove mine a crush zone
and dyke extend eastwards along the strike of the Strontian Main Vein; however,
to the west of the Whitesmith mine the evidence of a westward extension of the
Main Vein is insubstantial. A number of crush zones and associated dykes have
been identified in the Corrantee-Whitesmith area. Probable ext_ensions are
indicated to a number of known veins in the vicinity of the Fee Donald mine.
The rss~llts merit geophysical, geological and possibly geochemical follow-up
'Selfish herds' of guppies follow complex movement rules, but not when information is limited
Under the threat of predation, animals can decrease their level of risk by moving towards other individuals to form compact groups. A significant body of theoretical work has proposed multiple movement rules, varying in complexity, which might underlie this process of aggregation. However, if and how animals use these rules to form compact groups is still not well under- stood, and how environmental factors affect the use of these rules even less so. Here, we evaluate the success of different movement rules, by comparing their predictions with the movement seen when shoals of guppies ( Poecilia reticulata ) form under the threat of predation. We repeated the experiment in a turbid environment to assess how the use of the movement rules changed when visual information is reduced. During a simulated predator attack, guppies in clear water used complex rules that took multiple neighbours into account, forming compact groups. In turbid water, the difference between all rule predictions and fish movement paths increased, particularly for complex rules, and the resulting shoals were more fragmented than in clear water. We conclude that guppies are able to use complex rules to form dense aggregations, but that environmental factors can limit their ability to do so
Turbidity weakens selection for assortment in body size in groups
Prey animals commonly associate with similar-looking individuals to reduce predation risk, via a reduction in predator targeting accuracy (the confusion effect) and preferential targeting of distinct individuals (the oddity effect). These effects are mediated by body size, as predators often preferentially select large-bodied individuals, which are therefore at an increased risk within a group. The selection pressure to avoid oddity by associating with similar sized group mates is stronger for large individuals than small. This selection depends on the ability of both predators and prey to accurately assess body size and respond accordingly. In aquatic systems, turbidity degrades the visual environment and negatively impacts on the ability of predators to detect (and consume) prey. We assessed the effect of algal turbidity on predatorâprey interactions in the context of the oddity effect from the perspective of both predator and prey. From a predatorâs perspective, we find that 9-spined sticklebacks preferentially target larger Daphnia in mixed swarms in clear water, but not in turbid water, although the difference in attack rates is not statistically significant. When making shoaling decisions, large sticklebacks preferentially associate with size-matched individuals in clear water, but not turbid water, whereas small individuals showed no social preference in either clear or turbid water. We suggest that a reduced ability or motivation to discriminate between prey in turbid water relaxes the predation pressure on larger prey individuals allowing greater flexibility in shoaling decisions. Thus, turbidity may play a significant role in predatorâprey interactions, by altering predatorâprey interactions
Design in the Time of Policy Problems
This paper discusses an emerging context in which design expertise is being applied â the making of government policy. It reviews existing research and identifies the claim that design changes the nature of policy making. The paper then adapts a conceptual framework from social studies of science to make sense of the encounter between design and policy making. The paper applies this lens to an empirical account of design being applied to policy making in a team in the UK government. The findings are that in addition to supporting officials in applying design approaches, the teamâs work shapes the emergence of hybrid policy making practices, and at times problematizes the nature of policy making. It does this within logics of accountability, innovation, and reordering. The contribution is to provide empirical detail and a nuanced account of what happens in these encounter between design expertise and policy making practice
21st CenturyâŠ19th CenturyâŠ6th Century BC Skills
During July I spent some time in Ireland; in the beautiful,
south-west corner that is Kerry. Whilst there, I was reading
a bit of the local history and came across some quite
mind-boggling technology. In a gently shelving sandy cove
by Waterville lies the remains of an astonishing leap of
faith by a group of Victorian entrepreneurs. Sticking out of
the cliff is the tattered end of a telegraph cable that ran
across 2000 miles of ocean to Newfoundland and
thereafter overland to New York. The south-west tip of
Kerry (Valentia island) was chosen (in the 1850s) as the
take-off point and âHearts Contentâ bay in Newfoundland
the receiving point. But in between lay 2000 miles of wild
ocean that is variously 2-3 miles deep
Tasks in Technology: An analysis of their purposes and effects
Introduction for the 2015 DATA Special Edition This paper was written in 1993 and was published in The International Journal of Technology and Design Education. 1994 Springer 4(3): 241-256. The paper concerns the nature of the tasks that initiate and drive technological activity. It is set in the context of two research projects that we conducted in TERU; the Assessment of Performance Unit project in Design & Technology (1985 to 1991) and the Economic and Social Research Council project âUnderstanding Technological Approachesâ (UTA) (1992-1994). The former was a large scale national survey of performance in schools - involving tests on 10,000 learners in 700 schools, and the latter is a small scale study (80 learners in 20 schools) examining in detail the processes that learners engage in as they tackle technological tasks. However, the wider context of this paper concerns the English and Welsh National Curriculum (NC) implementation programme that had been launched in 1990. It caused a huge storm both in the curriculum generally and in design & technology (d&t) in particular. In the wider curriculum the assessment arrangements surrounding the Standard Assessment Tasks had been so badly designed that in 1992 teachers and schools had boycotted the whole process. And in d&t, the âOrderâ that defined what teachers should do in the classroom/studio/workshop appeared to make very different demands on teachers than had previously been the case. The Order defined d&t in four âAttainment Targetsâ, the first of which (AT1) was âIdentifying Needs and Opportunitiesâ. This (at least) implied that learners themselves should be doing that âidentifyingâ, and in 1990 that was far from common practice. At exactly this moment we undertook the ESRC: UTA project that enabled us to collect the data that would inform this issue. We followed in detail the tasks that teachers set or negotiated with learners and examined the consequences of these tasks on â subsequent actions
Effect of Pyrolysis on the Removal of Antibiotic Resistance Genes and Class I Integrons from Municipal Wastewater Biosolids
Wastewater biosolids represent a significant reservoir of antibiotic resistance genes (ARGs). While current biosolids treatment technologies can reduce ARG levels in residual wastewater biosolids, observed removal rates vary substantially. Pyrolysis is an anoxic thermal degradation process that can be used to convert biosolids into energy rich products including py-gas and py-oil, and a beneficial soil amendment, biochar. Batch pyrolysis experiments conducted on municipal biosolids revealed that the 16S rRNA gene, the ARGs erm(B), sul1, tet(L), tet(O), and the integrase gene of class 1 integrons (intI1) were significantly reduced at pyrolysis temperatures ranging from 300â700 °C, as determined by quantitative polymerase chain reaction (qPCR). Pyrolysis of biosolids at 500 °C and higher resulted in approximately 6-log removal of the bacterial 16S rRNA gene. ARGs with the highest observed removals were sul1 and tet(O), which had observed reductions of 4.62 and 4.04-log, respectively. Pyrolysis reaction time had a significant impact on 16S rRNA, ARG and intI1 levels. A pyrolysis residence time of 5 minutes at 500 °C reduced all genes to below detection limits. These results demonstrate that pyrolysis could be implemented as a biosolids polishing treatment technology to substantially decrease the abundance of total bacteria (i.e., 16S rRNA), ARGs and intI1 prior to land application of municipal biosolids
Turbidity influences individual and group level responses to predation in guppies, Poecilia reticulata
© 2015 The Association for the Study of Animal Behaviour. Increasing turbidity (either sedimentary or organic) from anthropogenic sources has significant negative impacts on aquatic fauna, both directly and indirectly by disrupting behaviour. In particular, antipredator responses of individuals are reduced, which has been attributed to a reduced perception of risk. Here, we explored the effect of turbidity on shoaling behaviour, which is known to carry important antipredator benefits, predicting that fish in turbid water should show reduced shoal cohesion (increased interindividual distances) and reduced responses to a simulated predatory threat. We explored both the individual and shoal level responses to a predation threat at four different levels of turbidity. At the shoal level, we found that shoals were less cohesive in more turbid water, but that there was no effect of turbidity on shoal level response to the predation threat. At an individual level, guppies in turbid water were more likely to freeze (rather than dart then freeze), and those that darted moved more slowly and over a shorter distance than those in clear water. Fish in turbid water also took longer to recover from a predation threat than fish in clear water. We suggest that because fish in turbid water behaved in a manner more similar to that expected from lone fish than to those in a shoal, the loss of visual contact between individuals in turbid water explains the change in behaviour, rather than a reduced perception of individual risk as is widely supposed. We suggest that turbidity could lead to a reduced collective response to predators and a loss of the protective benefits of shoaling
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