889 research outputs found
Sleep Analytics and Online Selective Anomaly Detection
We introduce a new problem, the Online Selective Anomaly Detection (OSAD), to
model a specific scenario emerging from research in sleep science. Scientists
have segmented sleep into several stages and stage two is characterized by two
patterns (or anomalies) in the EEG time series recorded on sleep subjects.
These two patterns are sleep spindle (SS) and K-complex. The OSAD problem was
introduced to design a residual system, where all anomalies (known and unknown)
are detected but the system only triggers an alarm when non-SS anomalies
appear. The solution of the OSAD problem required us to combine techniques from
both machine learning and control theory. Experiments on data from real
subjects attest to the effectiveness of our approach.Comment: Submitted to 20th ACM SIGKDD Conference on Knowledge Discovery and
Data Mining 201
Teegi: Tangible EEG Interface
We introduce Teegi, a Tangible ElectroEncephaloGraphy (EEG) Interface that
enables novice users to get to know more about something as complex as brain
signals, in an easy, en- gaging and informative way. To this end, we have
designed a new system based on a unique combination of spatial aug- mented
reality, tangible interaction and real-time neurotech- nologies. With Teegi, a
user can visualize and analyze his or her own brain activity in real-time, on a
tangible character that can be easily manipulated, and with which it is
possible to interact. An exploration study has shown that interacting with
Teegi seems to be easy, motivating, reliable and infor- mative. Overall, this
suggests that Teegi is a promising and relevant training and mediation tool for
the general public.Comment: to appear in UIST-ACM User Interface Software and Technology
Symposium, Oct 2014, Honolulu, United State
Multi-Q mesoscale magnetism in CeAuSb
We report the discovery of a field driven transition from a striped to woven
Spin Density Wave (SDW) in the tetragonal heavy fermion compound CeAuSb.
Polarized along , the sinusoidal SDW amplitude is 1.8(2) /Ce for
=6.25(10) K with wavevector (). For , harmonics appearing at
evidence a striped magnetic texture below T. Above , these are replaced by woven harmonics at
until T, where satellites vanish and magnetization non-linearly
approaches saturation at 1.64(2) /Ce for T.Comment: 5 pages, 4 figure
Diagnosis by Documentary: Professional Responsibilities in Informal Encounters
Most work addressing clinical workers' professional responsibilities concerns the norms of conduct within established professional-patient relationships, but such responsibilities may extend beyond the clinical context. We explore health workers' professional responsibilities in such "informal" encounters through the example of a doctor witnessing the misdiagnosis and mistreatment of a serious long-term condition in a television documentary, arguing that neither internalist approaches to professional responsibility (such as virtue ethics or care ethics) nor externalist ones (such as the "social contract" model) provide sufficiently clear guidance in such situations. We propose that a mix of both approaches, emphasizing the noncomplacency and practical wisdom of virtue ethics, but grounding the normative authority of virtue in an external source, is able to engage with the health worker's responsibilities in such situations to the individual, the health care system, and the population at large
The transformation of the forest steppe in the lower Danube Plain of south-eastern Europe : 6000 years of vegetation and land use dynamics
Forest steppes are dynamic ecosystems, highly susceptible to changes in climate and land use. Here we examine the Holocene history of the European forest steppe ecotone in the Lower Danube Plain to better understand its sensitivity to climate fluctuations and human impact, and the timing of its transition into a cultural forest steppe. We used multi-proxy analyses (pollen, n-alkane, coprophilous fungi, charcoal, and geochemistry) of a 6000-year sequence from Lake Oltina (SE Romania), combined with a REVEALS model of quantitative vegetation cover. We found the greatest tree cover, composed of xerothermic (Carpinus orientalis and Quercus) and temperate (Carpinus betulus, Tilia, Ulmus and Fraxinus) tree taxa between 6000 and 2500âcalâyrâBP. Maximum tree cover (~â50â%) occurred between 4200 and 2500âcalâyrâBP at a time of wetter climatic conditions. Compared to other European forest steppe areas, the dominance of Carpinus orientalis represents the most distinct feature of the woodland's composition during that time. Forest loss was under way by 2500âyrâBP (Iron Age) with REVEALS estimates indicating a fall to ~â20â% tree cover from the mid-Holocene forest maximum linked to clearance for agriculture, while climate conditions remained wet. Biomass burning increased markedly at 2500âcalâyrâBP suggesting that fire was regularly used as a management tool until 1000âcalâyrâBP when woody vegetation became scarce. A sparse tree cover, with only weak signs of forest recovery, then became a permanent characteristic of the Lower Danube Plain, highlighting recurring anthropogenic pressure. The timing of anthropogenic ecosystem transformation here (2500âcalâyrâBP) was in between that in central eastern (between 3700 and 3000âcalâyrâBP) and eastern (after 2000âcalâyrâBP) Europe. Our study is the first quantitative land cover estimate at the forest steppe ecotone in south eastern Europe spanning 6000 years and provides critical empirical evidence that the present-day forest steppe/woodlands reflects the potential natural vegetation in this region under current climate conditions. This study also highlights the potential of n-alkane indices for vegetation reconstruction, particularly in dry regions where pollen is poorly preserved
Cluster Spin Glass Distribution Functions in LaSrCuO
Signatures of the cluster spin glass have been found in a variety of
experiments, with an effective onset temperature that is frequency
dependent. We reanalyze the experimental results and find that they are
characterized by a distribution of activation energies, with a nonzero glass
transition temperature . While the distribution of activation
energies is the same, the distribution of weights depends on the process.
Remarkably, the weights are essentially doping independent.Comment: 5 pages, 5 ps figure
Webteaching: sequencing of subject matter in relation to prior knowledge of pupils
Two experiments are discussed in which the sequencing procedure of webteaching is compared with a linear sequence for the presentation of text material.\ud
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In the first experiment variations in the level of prior knowledge of pupils were studied for their influence on the sequencing mode of text presentation. Prior knowledge greatly reduced the effect of the size of sequencing procedures.\ud
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In the second experiment pupils with a low level of prior knowledge studied a text, following either a websequence or a linear sequence. Webteaching was superior to linear teaching on a number of dependent variables. It is concluded that webteaching is an effective sequencing procedure in those cases where substantial new learning is required
More than just an eagle killer: The freshwater cyanobacterium Aetokthonos hydrillicola produces highly toxic dolastatin derivatives
Cyanobacteria are infamous producers of toxins. While the toxic potential of planktonic cyanobacterial blooms is well documented, the ecosystem level effects of toxigenic benthic and epiphytic cyanobacteria are an understudied threat. The freshwater epiphytic cyanobacterium Aetokthonos hydrillicola has recently been shown to produce the âeagle killerâ neurotoxin aetokthonotoxin (AETX) causing the fatal neurological disease vacuolar myelinopathy. The disease affects a wide array of wildlife in the southeastern United States, most notably waterfowl and birds of prey, including the bald eagle. In an assay for cytotoxicity, we found the crude extract of the cyanobacterium to be much more potent than pure AETX, prompting further investigation. Here, we describe the isolation and structure elucidation of the aetokthonostatins (AESTs), linear peptides belonging to the dolastatin compound family, featuring a unique modification of the C-terminal phenylalanine-derived moiety. Using immunofluorescence microscopy and molecular modeling, we confirmed that AEST potently impacts microtubule dynamics and can bind to tubulin in a similar matter as dolastatin 10. We also show that AEST inhibits reproduction of the nematode Caenorhabditis elegans. Bioinformatic analysis revealed the AEST biosynthetic gene cluster encoding a nonribosomal peptide synthetase/polyketide synthase accompanied by a unique tailoring machinery. The biosynthetic activity of a specific N-terminal methyltransferase was confirmed by in vitro biochemical studies, establishing a mechanistic link between the gene cluster and its product
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