679 research outputs found
Open the treasure room and decolonize the museum
Inaugural lecture delivered by Prof.dr. Tinde van Andel on the occasion of the acceptance of the position of Special professor of the Clusius chair of
History of Botany and Gardens at Leiden University Friday 6 January 2017Inaugural lecture delivered by Prof.dr. Tinde van Andel on the occasion of the acceptance of the position of Special professor of the Clusius chair of History of Botany and Gardens at Leiden University Friday 6 January 201
The intersection between the Mid-Atlantic Ridge and the Vema Fracture zone in the North Atlantic
Near 11°N, the Mid-Atlantic Ridge is offset by the Verna Fracture. The hypothesis of sea-floor spreading has suggested that the fracture is a transform fault, and this has been confirmed by the first motion studies of recent earthquakes along the fracture. The fault zone is developed as a deep and narrow east-west trending through, bordered on the south side by a high and steep rocky wall representing an uplifted slice of crust...
Захист від недобросовісної конкуренції у медичній сфері: проблеми правововго регулювання
Кожна людина має право на здорові умови життя, але напевно ще жодному не вдавалось уникнути звернень до лікарень, аптек, та інших організацій медичної сфери. Метою даної статті є дослідження захисту від недобросовісної конкуренції у медичній сфері в Україні та інших країнах та розроблення наукових рекомендацій щодо вдосконалення українського законодавства щодо врегулювання відносин щодо здійснення господарювання в медичній сфері
When a fly ball is out of reach: catchability judgments are not based on optical acceleration cancelation.
The optical acceleration cancelation (OAC) strategy, based on Chapman’s (1968) analysis of the outfielder problem, has been the dominant account for the control of running to intercept fly balls approaching head on. According to the OAC strategy, outfielders will arrive at the interception location just in time to catch the ball when they keep optical acceleration zero. However, the affordance aspect of this task, that is, whether or not an approaching fly ball is catchable, is not part of this account. The present contribution examines whether the scope of the OAC strategy can be extended to also include the affordance aspect of running to catch a fly ball. This is done by considering a fielder’s action boundaries (i.e., maximum running velocity and – acceleration) in the context of the OAC strategy. From this, only when running velocity is maximal and optical acceleration is non-zero, a fielder would use OAC to perceive a fly ball as uncatchable. The present contribution puts this hypothesis to the test. Participants were required to try to intercept fly balls projected along their sagittal plane. Some fly balls were catchable whereas others were not. Participants were required to catch as many fly balls as possible and to call ‘no’ when they perceived a fly ball to be uncatchable. Participants’ running velocity and –acceleration at the moment of calling ‘no’ were examined. Results showed that participants’ running velocity was submaximal before or while calling ‘no’. Also running acceleration was often submaximal. These results cannot be explained by the use of OAC in judging catchability and ultimately call for a new strategy of locomotor control in running to catch a fly ball
Scientists’ Warning on Climate Change and Medicinal Plants
The recent publication of a World Scientists’ Warning to Humanity highlighted the fact that climate change, absent strenuous mitigation or adaptation efforts, will have profound negative effects for humanity and other species, affecting numerous aspects of life. In this paper, we call attention to one of these aspects, the effects of climate change on medicinal plants. These plants provide many benefits for human health, particularly in communities where Western medicine is unavailable. As for other species, their populations may be threatened by changing temperature and precipitation regimes, disruption of commensal relationships, and increases in pests and pathogens, combined with anthropogenic habitat fragmentation that impedes migration. Additionally, medicinal species are often harvested unsustainably, and this combination of pressures may push many populations to extinction. A second issue is that some species may respond to increased environmental stresses not only with declines in biomass production but with changes in chemical content, potentially affecting quality or even safety of medicinal products. We therefore recommend actions including conservation and local cultivation of valued plants, sustainability training for harvesters and certification of commercial material, preservation of traditional knowledge, and programs to monitor raw material quality, in addition to, of course, efforts to mitigate climate change
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