144 research outputs found
Micro-evolutionary diversification among Indian Ocean parrots: temporal and spatial changes in phylogenetic diversity as a consequence of extinction and invasion
Almost 90% of global bird extinctions have occurred on islands. The loss of endemic spe- cies from island systems can dramatically alter evolutionary trajectories of insular species biodiversity, resulting in a loss of evolutionary diversity important for species adaptation to changing environments. The Western Indian Ocean islands have been the scene of evolution for a large number of endemic parrots. Since their discovery in the 16th cen- tury, many of these parrots have become extinct or have declined in numbers. Alongside the extinction of species, a number of the Indian Ocean islands have experienced coloni- zation by highly invasive parrots, such as the Ring-necked Parakeet Psittacula krameri. Such extinctions and invasions can, on an evolutionary timescale, drive changes in spe- cies composition, genetic diversity and turnover in phylogenetic diversity, all of which can have important impacts on species potential for adaptation to changing environmen- tal and climatic conditions. Using mtDNA cytochrome b data, we resolve the taxonomic placement of three extinct Indian Ocean parrots: the Rodrigues Psittacula exsul, Sey- chelles Psittacula wardi and Reunion Parakeets Psittacula eques. This case study quantifies how the extinction of these species has resulted in lost historical endemic phylogenetic diversity and reduced levels of species richness, and illustrates how it is being replaced by non-endemic invasive forms such as the Ring-necked Parakeet. Finally, we use our phylogenetic framework to identify and recommend a number of phylogenetically appro- priate ecological replacements for the extinct parrots. Such replacements may be intro- duced once invasive forms have been cleared, to rejuvenate ecosystem function and restore lost phylogenetic diversity
All-Optical Broadband Excitation of the Motional State of Trapped Ions
We have developed a novel all-optical broadband scheme for exciting,
amplifying and measuring the secular motion of ions in a radio frequency trap.
Oscillation induced by optical excitation has been coherently amplified to
precisely control and measure the ion's secular motion. Requiring only laser
line-of-sight, we have shown that the ion's oscillation amplitude can be
precisely controlled. Our excitation scheme can generate coherent motion which
is robust against variations in the secular frequency. Therefore, our scheme is
ideal to excite the desired level of oscillatory motion under conditions where
the secular frequency is evolving in time. Measuring the oscillation amplitude
through Doppler velocimetry, we have characterized the experimental parameters
and compared them with a molecular dynamics simulation which provides a
complete description of the system.Comment: 8 pages, 10 figure
eCute: Difference is good
This paper provides an overview of ongoing research on cultural and emotional learning, thereby utilizing engaging roleplay with synthetic characters. The paper explains the underlying learning objectives and provides an overview of how we intend to achieve them. This includes a technical framework integrating affective AI characters and innovative interaction technologies. The framework will be used to realize a virtual learning environment hosting the synthetic characters. Finally a brief description of an evaluation approach for the anticipated learning objectives is given
Traveller–Intercultural training with intelligent agents for young adults
In this paper we describe Traveller, an intercultural training tool for young adults. Traveller is based on an original theoretical framework which focuses on key concepts of intercultural training. By progressing through a creative story, users are able to engage via a novel interaction paradigm with intelligent virtual characters that incorporate different simulated cultures which can
lead to misunderstandings and sometimes conflicts. Through the use of an innovative evaluation approach, users will gain a greater understanding of the behavioural differences between these characters, and thereby learn to become more effective at dealing with misunderstandings due to differences in culture
Beyond the Libet clock: modality variants for agency measurements
The Sense of Agency (SoA) refers to our capability to control our own actions and influence the world around us. Recent research in HCI has been exploring SoA to provide users an instinctive sense of “I did that” as opposed to “the system did that”. However, current agency measurements are limited. The Intentional Binding (IB) paradigm provides an implicit measure of the SoA. However, it is constrained by requiring high visual attention to a “Libet clock” onscreen. In this paper, we extend the timing stimulus through auditory and tactile cues. Our results demonstrate that audio timing through voice commands and haptic timing through tactile cues on the hand are alternative techniques to measure the SoA using the IB paradigm. They both address limitations of the traditional method (e.g., lack of engagement and visual demand). We discuss how our results can be applied to measure SoA in tasks involving different interactive scenarios common in HCI
History of clinical transplantation
How transplantation came to be a clinical discipline can be pieced together by perusing two volumes of reminiscences collected by Paul I. Terasaki in 1991-1992 from many of the persons who were directly involved. One volume was devoted to the discovery of the major histocompatibility complex (MHC), with particular reference to the human leukocyte antigens (HLAs) that are widely used today for tissue matching.1 The other focused on milestones in the development of clinical transplantation.2 All the contributions described in both volumes can be traced back in one way or other to the demonstration in the mid-1940s by Peter Brian Medawar that the rejection of allografts is an immunological phenomenon.3,4 © 2008 Springer New York
Understanding Scientific Practices: The Role of Robustness Notions
This article explores the role of `robustness-notions¿ in an account of the engineering sciences. The engineering sciences aim at technological production of, and intervention with phenomena relevant to the (dis-)functioning of materials and technological devices, by means of scientific understanding thereof. It is proposed that different kinds of robustness-notions enable and guide scientific research: (1) Robustness is as a metaphysical belief that we have about the physical world ¿ i.e., we believe that the world is robust in the sense that the same physical conditions will always produce the same effects. (2) `Same conditions ¿ same effects¿ functions as a regulative
principle that enables and guides scientific research because it points to, and justifies methodological notions. (3) Repetition, variance and multiple-determination function as methodological criteria for scientific methods that justify the acceptance of epistemological and ontological results. (4) Reproducibility and stability function as ontological criteria for the acceptance of phenomena described by A¿B. (5) Reliability functions as an epistemological criterion for the acceptance of epistemological results, in particular law¿like knowledge of a conditional form: ¿A¿B, provided Cdevice, and unless other known and/or unknown causally relevant conditions.¿ The crucial question is how different kinds of robustness¿notions are related and how they play their part in the production and acceptance of scientific results. Focus is on production and acceptance of physical phenomena and the rule-like knowledge thereof. Based
on an analysis of how philosoophy of science tradtionally justified scientific knowledge, I propose a general schema that specifies how inferences to the claim that a scientific result has a certain epistem ological property (such as truth) are justified by scientific methods that meet specific methodological criteria. It is proposed that `same conditions ¿
same effects¿ as a regulative criterion justifies `repetition, variation and ultiple¿determination¿ as methodological criteria for the production and acceptance of (ontological and epistemological) scientific result
Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET
The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR
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