405 research outputs found
Operant Conditioning in the Psittacine, Amazona amazonica
Two Orange-winged Amazon Parrots, (Amazona amazonica) were subjected to operant conditioning involving three tests: two-choice spatial discrimination and reversal, three-choice color discrimination and reversal, and the oddity principle. Results of the habit reversal tests were compared to those of Gossett (1968) to determine the phylogenetic ranking of the learning capabilities of psittacines. In the first two habit reversal tests, the subjects completed twenty reversals using sunflower seeds as positive reinforcements. In the oddity principle test, the parrots completed the equivalent of 20 reversals, again using sunflower seeds. Criterion was met when they completed 8 consecutive correct choices with 11 out of the last 12 correct. As Gossett did not attempt the oddity principle, results of this test were compared to those of Warren (1960).
Results of the discrimination and reversal tests were quite similar to those obtained by Gossett in his study of another species of Amazon Parrot. The birds conditioned rapidly but failed to form a learning set in all instances and could not generalize the oddity principle. when comparing the results of that test to those obtained by Warren.
These results substantiate those obtained by Gossett and show remarkable similarity in the learning capabilities of the psittacines. With regard to phylogenetic ranking, these birds do not perform as well as passerines, but superior to the other species tested by Gossett
The Emperor Has No Clothes: Solidifying Inconsistencies in Judges\u27 Preference
Several leaders representing the forensics world were surveyed to examine the role judges preference plays in the outcomes of forensics tournaments. Similarities and differences concerning the definition of judge\u27s preference emerged as dominant themes. Implications of this study offer new questions concerning definitions of judge’s preference and the role tabulation should play in the formation of leaders in forensics
Fabrication of antenna-coupled KID array for Cosmic Microwave Background detection
Kinetic Inductance Detectors (KIDs) have become an attractive alternative to
traditional bolometers in the sub-mm and mm observing community due to their
innate frequency multiplexing capabilities and simple lithographic processes.
These advantages make KIDs a viable option for the detectors
needed for the upcoming Cosmic Microwave Background - Stage 4 (CMB-S4)
experiment. We have fabricated antenna-coupled MKID array in the 150GHz band
optimized for CMB detection. Our design uses a twin slot antenna coupled to
inverted microstrip made from a superconducting Nb/Al bilayer and SiN,
which is then coupled to an Al KID grown on high resistivity Si. We present the
fabrication process and measurements of SiN microstrip resonators.Comment: 7 pages, 9 figures, submitted to Journal of Low Temperature Physic
Simulating Light-Weight Personalised Recommender Systems in Learning Networks: A Case for Pedagogy-Oriented and Rating-Based Hybrid Recommendation Strategies
Recommender systems for e-learning demand specific pedagogy-oriented and hybrid recommendation strategies. Current systems are often based on time-consuming, top down information provisioning combined with intensive data-mining collaborative filtering approaches. However, such systems do not seem appropriate for Learning Networks where distributed information can often not be identified beforehand. Providing sound way-finding support for lifelong learners in Learning Networks requires dedicated personalised recommender systems (PRS), that offer the learners customised advise on which learning actions or programs to study next. Such systems should also be practically feasible and be developed with minimized effort. Currently, such so called light-weight PRS systems are scarcely available. This study shows that simulation studies can support the analysis and optimisation of PRS requirements prior to starting the costly process of their development, and practical implementation (including testing and revision) during field experiments in real-life learning situations. This simulation study confirms that providing recommendations leads towards more effective, more satisfied, and faster goal achievement. Furthermore, this study reveals that a light-weight hybrid PRS-system based on ratings is a good alternative for an ontology-based system, in particular for low-level goal achievement. Finally, it is found that rating-based light-weight hybrid PRS-systems enable more effective, more satisfied, and faster goal attainment than peer-based light-weight hybrid PRS-systems (incorporating collaborative techniques without rating).Recommendation Strategy; Simulation Study; Way-Finding; Collaborative Filtering; Rating
The investigation of properties of investment casting moulds reinforced with ceramic fibre
Abstract Increasing of strength and permeability of the thin-walled investment casting ceramic moulds was the main goal of this work. Its essence is a new concept of the mould reinforcement, i.e. the full or the significant replacement of grain silica materials by fibrous aluminosilicate materials. An addition of ceramic fibre increase the permeability and green strength value of the ceramic shell mould material which allows for safe burning out of the pattern set
Understanding the dynamic momentum aperture of the Advanced Light Source
The lifetime of a light source with small emittance like the Advanced Light Source (ALS) is usually limited by the momentum acceptance of the ring. Large momentum acceptances are reached by providing enough RF voltage and by avoiding a degradation of the dynamic momentum aperture. At the ALS the size of the momentum acceptance depends strongly on the transverse dynamics. It is very sensitive to machine conditions such as the tunes and chromaticities since depending on those conditions the Touschek scattered particles explore different resonance regions in the phase space. In this paper we show that by using a single-turn ’pinger’ magnet together with turn-byturn beam position monitors (BPM) one can identify the cause of a reduction in momentum acceptance and take steps to improve the acceptance
Electronic self-doping of Mo-states in A2FeMoO6 (A=Ca, Sr and Ba) half-metallic ferromagnets - a Nuclear Magnetic Resonance study
A systematic study of (A,A')2FeMoO6 (A,A'=Ca, Sr, Ba) ferromagnetic oxides
with double perovskite structure has been performed using 95,97Mo and 57Fe NMR
spectroscopy. These oxides are isoelectronic but have substantially different
Curie temperatures. The NMR analysis provides clear evidence that the magnetic
moment at Mo sites is not constant but varies sensitively with the ionic size
of the alkaline ions. The 95,97Mo frequency, and thus the electronic charge at
Mo ions, is found to be smaller in Ba and Ca than in Sr-based oxides. The
charge release from Mo sites is accompanied by an uptake at Fe sites, and thus
a self-doping Fe-Mo process is observed. This process is controlled by relevant
structural parameters: the Fe-O-Mo bond length and bending. A clear
relationship between the Curie temperature and the magnetic moment and thus
electron density at Mo sites has been disclosed. The relevance of these
findings for the understanding of ferromagnetic coupling in double perovskites
is discussed.Comment: 26 pages, 8 figure
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