311 research outputs found
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Being fluent and keeping looking
The complexities of the many concepts and models around information literacy are considered, and some personal views given as to how they may best be clarified, both theoretically and practically. A slightly adapted idea of the concept of information fluency can serve as a main general purpose for the promotion of information literacy, expressed as a more specific meta-model for the prevailing technological environment, and as still more specific components for a particular context. The focus of this relatively stable general formulation is on understanding, rather than skills or competences. It can incorporate the need for education, advice and counseling, as well as information provision, and with domain-specific literacies, as well as supporting personal information literacy
Robotic weeding – from concept to trials
This paper reports on the use of robotic selective mechanical cultivation as an alternative method to herbicide control for managing weed species in zero-till cropping systems. Existing best-practice technology in weed spot spraying utilises infrared technology to detect and selectively spray weeds using herbicide at quantities significantly less than those used in normal blanket spray applications. This reduction in the herbicide de- creases operational costs and can be beneficial for the environment; however, the capital investment in the technology is substantial for farmers who wish to own and operate their equipment. While effective in reducing overall herbicide usage, the technology has done little to tackle the rapid evolution of herbicide resistant weed species. As a potential solution to this issue, our research over the past three years has been focused on the development of non-chemical methods of weed management utilising robot-enabled selective mechanical weeding. Used in conjunction with a robotic vehicle platform, a mechanical weeding array is capable of working throughout the day and night. The weeding tools have been designed to be removable and inter- changeable, allowing the use of tools especially designed for different weed species, weed densities, and soil types. The system developed consists of a one-degree-of-freedom array of weeding tines, actuated into the ground in time to remove individual weeds. Sensing of the weeds is enabled by a vision-based plant detection and classification system, while the timing for the implement actuation to hit the weed is determined as a function of the robot speed. The field trials reported in this paper demonstrate the potential of this robotic system for individualised weed treatment and multi-mode weed management methods. In particular, a trial of the mechanical weeding array in a fallow field over six weeks maintained the weed coverage in robot treated sections to be 1.5%, compared to 37% in the control areas not treated by the robot—a reduction in excess of 90% in weed coverage
Narrow-band anisotropic electronic structure of ReS2
We have used angle resolved photoemission spectroscopy to investigate the band structure of ReS2, a transition-metal dichalcogenide semiconductor with a distorted 1T crystal structure. We find a large number of narrow valence bands, which we attribute to the combined influence of the structural distortion and spin-orbit coupling. We further image how this leads to a strong in-plane anisotropy of the electronic structure, with quasi-one-dimensional bands reflecting predominant hopping along zig-zag Re chains. We find that this does not persist up to the top of the valence band, where a more three-dimensional character is recovered with the fundamental band gap located away from the Brillouin zone centre along kz. These experiments are in good agreement with our density-functional theory calculations, shedding new light on the bulk electronic structure of ReS2, and how it can be expected to evolve when thinned to a single layer.PostprintPeer reviewe
Fermiology and superconductivity of topological surface states in PdTe2
We gratefully acknowledge support from the Leverhulme Trust, the Engineering and Physical Sciences Research Council, UK (Grant Nos. EP/M023427/1 and EP/I031014/1), the Royal Society. JC, MJN, LB, VS, and JMR acknowledge EPSRC for PhD studentship support through grant Nos. EP/K503162/1, EP/G03673X/1, EP/L505079/1, and EP/L015110/1.We study the low-energy surface electronic structure of the transition-metal dichalcogenide superconductor PdTe2 by spin- and angle-resolved photoemission, scanning tunneling microscopy, and density-functional theory-based supercell calculations. Comparing PdTe2 with its sister compound PtSe2, we demonstrate how enhanced interlayer hopping in the Te-based material drives a band inversion within the antibonding p -orbital manifold well above the Fermi level. We show how this mediates spin-polarized topological surface states which form rich multivalley Fermi surfaces with complex spin textures. Scanning tunneling spectroscopy reveals type-II superconductivity at the surface, and moreover shows no evidence for an unconventional component of its superconducting order parameter, despite the presence of topological surface states.PostprintPeer reviewe
Bandit strategies in social search: the case of the DARPA red balloon challenge
Collective search for people and information has tremendously benefited from emerging communication technologies that leverage the wisdom of the crowds, and has been increasingly influential in solving time-critical tasks such as the DARPA Network Challenge (DNC, also known as the Red Balloon Challenge). However, while collective search often invests significant resources in encouraging the crowd to contribute new information, the effort invested in verifying this information is comparable, yet often neglected in crowdsourcing models. This paper studies how the exploration-verification trade-off displayed by the teams modulated their success in the DNC, as teams had limited human resources that they had to divide between recruitment (exploration) and verification (exploitation). Our analysis suggests that team performance in the DNC can be modelled as a modified multi-armed bandit (MAB) problem, where information arrives to the team originating from sources of different levels of veracity that need to be assessed in real time. We use these insights to build a data-driven agent-based model, based on the DNC’s data, to simulate team performance. The simulation results match the observed teams’ behavior and demonstrate how to achieve the best balance between exploration and exploitation for general time-critical collective search tasks.</p
Kazališni fragment II
Engineering and enhancing inversion symmetry breaking in solids is a major
goal in condensed matter physics and materials science, as a route to advancing
new physics and applications ranging from improved ferroelectrics for memory
devices to materials hosting Majorana zero modes for quantum computing. Here,
we uncover a new mechanism for realising a much larger energy scale of
inversion symmetry breaking at surfaces and interfaces than is typically
achieved. The key ingredient is a pronounced asymmetry of surface hopping
energies, i.e. a kinetic energy-driven inversion symmetry breaking, whose
energy scale is pinned at a significant fraction of the bandwidth. We show,
from spin- and angle-resolved photoemission, how this enables surface states of
3d and 4d-based transition-metal oxides to surprisingly develop some of the
largest Rashba-like spin splittings that are known. Our findings open new
possibilities to produce spin textured states in oxides which exploit the full
potential of the bare atomic spin-orbit coupling, raising exciting prospects
for oxide spintronics. More generally, the core structural building blocks
which enable this are common to numerous materials, providing the prospect of
enhanced inversion symmetry breaking at judiciously-chosen surfaces of a
plethora of compounds, and suggesting routes to interfacial control of
inversion symmetry breaking in designer heterostructures
Conceptions of learning factors in postgraduate health sciences master students: a comparative study with nonhealth science students and between genders
Background: The students’ conceptions of learning in postgraduate health science master studies are poorly
understood. The aim of this study was to compare the factors influencing conceptions of learning in health
sciences and non-health sciences students enrolled in postgraduate master programs in order to obtain
information that may be useful for students and for future postgraduate programs.
Methods: A modified version of the Learning Inventory Conception Questionnaire (COLI) was used to compare
students’ conception learning factors in 131 students at the beginning of their postgraduate studies in health
sciences, experimental sciences, arts and humanities and social sciences.
Results: The present study demonstrates that a set of factors may influence conception of learning of health
sciences postgraduate students, with learning as gaining information, remembering, using, and understanding
information, awareness of duty and social commitment being the most relevant. For these students, learning as a
personal change, a process not bound by time or place or even as acquisition of professional competences, are less
relevant. According to our results, this profile is not affected by gender differences.
Conclusions: Our results show that the overall conceptions of learning differ among students of health sciences
and non-health sciences (experimental sciences, arts and humanities and social sciences) master postgraduate
programs. These finding are potentially useful to foster the learning process of HS students, because if they are
metacognitively aware of their own conception or learning, they will be much better equipped to self-regulate
their learning behavior in a postgraduate master program in health sciences.Supported by CTS-115 (Tissue Engineering Group of the University of Granada).
The funding body did not took part in the design of the study and collection,
analysis and interpretation of data and in writing the manuscript
The international politics of geoengineering: The feasibility of Plan B for tackling climate change
Geoengineering technologies aim to make large-scale and deliberate interventions in the climate system possible. A typical framing is that researchers are exploring a ‘Plan B’ in case mitigation fails to avert dangerous climate change. Some options are thought to have the potential to alter the politics of climate change dramatically, yet in evaluating whether they might ultimately reduce climate risks, their political and security implications have so far not been given adequate prominence. This article puts forward what it calls the ‘security hazard’ and argues that this could be a crucial factor in determining whether a technology is able, ultimately, to reduce climate risks. Ideas about global governance of geoengineering rely on heroic assumptions about state rationality and a generally pacific international system. Moreover, if in a climate engineered world weather events become something certain states can be made directly responsible for, this may also negatively affect prospects for ‘Plan A’, i.e. an effective global agreement on mitigation
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