1,085 research outputs found
Volume and functional outcome of intracerebral hemorrhage according to oral anticoagulant type
Objective: To compare intracerebral hemorrhage (ICH) volume and clinical outcome of non–vitamin K oral anticoagulants (NOAC)–associated ICH to warfarin-associated ICH.
Methods: In this multicenter cross-sectional observational study of patients with anticoagulant-associated ICH, consecutive patients with NOAC-ICH were compared to those with warfarin-ICH selected from a population of 344 patients with anticoagulant-associated ICH. ICH volume was measured by an observer blinded to clinical details. Outcome measures were ICH volume and clinical outcome adjusted for confounding factors.
Results: We compared 11 patients with NOAC-ICH to 52 patients with warfarin-ICH. The median ICH volume was 2.4 mL (interquartile range [IQR] 0.3–5.4 mL) for NOAC-ICH vs 8.9 mL (IQR 4.0–21.3 mL) for warfarin-ICH (p = 0.0028). In univariate linear regression, use of warfarin (difference in cube root volume 1.61; 95% confidence interval [CI] 0.69 to 2.53) and lobar ICH location (compared with nonlobar ICH; difference in cube root volume 1.52; 95% CI 2.20 to 0.85) were associated with larger ICH volumes. In multivariable linear regression adjusting for confounding factors (sex, hypertension, previous ischemic stroke, white matter disease burden, and premorbid modified Rankin Scale score [mRS]), warfarin use remained independently associated with larger ICH (cube root) volumes (coefficient 0.64; 95% CI 0.24 to 1.25; p = 0.042). Ordered logistic regression showed an increased odds of a worse clinical outcome (as measured by discharge mRS) in warfarin-ICH compared with NOAC-ICH: odds ratio 4.46 (95% CI 1.10 to 18.14; p = 0.037).
Conclusions: In this small prospective observational study, patients with NOAC-associated ICH had smaller ICH volumes and better clinical outcomes compared with warfarin-associated ICH
Complexity without chaos: Plasticity within random recurrent networks generates robust timing and motor control
It is widely accepted that the complex dynamics characteristic of recurrent
neural circuits contributes in a fundamental manner to brain function. Progress
has been slow in understanding and exploiting the computational power of
recurrent dynamics for two main reasons: nonlinear recurrent networks often
exhibit chaotic behavior and most known learning rules do not work in robust
fashion in recurrent networks. Here we address both these problems by
demonstrating how random recurrent networks (RRN) that initially exhibit
chaotic dynamics can be tuned through a supervised learning rule to generate
locally stable neural patterns of activity that are both complex and robust to
noise. The outcome is a novel neural network regime that exhibits both
transiently stable and chaotic trajectories. We further show that the recurrent
learning rule dramatically increases the ability of RRNs to generate complex
spatiotemporal motor patterns, and accounts for recent experimental data
showing a decrease in neural variability in response to stimulus onset
Positive words carry less information than negative words
We show that the frequency of word use is not only determined by the word
length \cite{Zipf1935} and the average information content
\cite{Piantadosi2011}, but also by its emotional content. We have analyzed
three established lexica of affective word usage in English, German, and
Spanish, to verify that these lexica have a neutral, unbiased, emotional
content. Taking into account the frequency of word usage, we find that words
with a positive emotional content are more frequently used. This lends support
to Pollyanna hypothesis \cite{Boucher1969} that there should be a positive bias
in human expression. We also find that negative words contain more information
than positive words, as the informativeness of a word increases uniformly with
its valence decrease. Our findings support earlier conjectures about (i) the
relation between word frequency and information content, and (ii) the impact of
positive emotions on communication and social links.Comment: 16 pages, 3 figures, 3 table
Does training with amplitude modulated tones affect tone-vocoded speech perception?
Temporal-envelope cues are essential for successful speech perception. We asked here whether training on stimuli containing temporal-envelope cues without speech content can improve the perception of spectrally-degraded (vocoded) speech in which the temporal-envelope (but not the temporal fine structure) is mainly preserved. Two groups of listeners were trained on different amplitude-modulation (AM) based tasks, either AM detection or AM-rate discrimination (21 blocks of 60 trials during two days, 1260 trials; frequency range: 4Hz, 8Hz, and 16Hz), while an additional control group did not undertake any training. Consonant identification in vocoded vowel-consonant-vowel stimuli was tested before and after training on the AM tasks (or at an equivalent time interval for the control group). Following training, only the trained groups showed a significant improvement in the perception of vocoded speech, but the improvement did not significantly differ from that observed for controls. Thus, we do not find convincing evidence that this amount of training with temporal-envelope cues without speech content provide significant benefit for vocoded speech intelligibility. Alternative training regimens using vocoded speech along the linguistic hierarchy should be explored
Investigating the effects of particle shape on normal compression and overconsolidation using DEM
Discrete element modelling of normal compression has been simulated on a sample of breakable two-ball clumps and compared to that of spheres. In both cases the size effect on strength is assumed to be that of real silica sand. The slopes of the normal compression lines are compared and found to be consistent with the proposed equation of the normal compression line. The values of the coefficient of earth pressure at rest K0,nc are also compared and related to the critical state fiction angles for the two materials. The breakable samples have then been unloaded to establish the stress ratios on unloading. At low overconsolidation ratios the values of K0 follow a well-established empirical relationship and realistic Poisson ratios are observed. On progressive unloading both samples head towards passive failure, and the values of the critical state lines in extension in q–p' space are found to be consistent with the critical state angles deduced from the values of K0 during normal compression. The paper highlights the important role of particle shape in governing the stress ratio during both normal compression and subsequent overconsolidation
Radio Emission from Ultra-Cool Dwarfs
The 2001 discovery of radio emission from ultra-cool dwarfs (UCDs), the very
low-mass stars and brown dwarfs with spectral types of ~M7 and later, revealed
that these objects can generate and dissipate powerful magnetic fields. Radio
observations provide unparalleled insight into UCD magnetism: detections extend
to brown dwarfs with temperatures <1000 K, where no other observational probes
are effective. The data reveal that UCDs can generate strong (kG) fields,
sometimes with a stable dipolar structure; that they can produce and retain
nonthermal plasmas with electron acceleration extending to MeV energies; and
that they can drive auroral current systems resulting in significant
atmospheric energy deposition and powerful, coherent radio bursts. Still to be
understood are the underlying dynamo processes, the precise means by which
particles are accelerated around these objects, the observed diversity of
magnetic phenomenologies, and how all of these factors change as the mass of
the central object approaches that of Jupiter. The answers to these questions
are doubly important because UCDs are both potential exoplanet hosts, as in the
TRAPPIST-1 system, and analogues of extrasolar giant planets themselves.Comment: 19 pages; submitted chapter to the Handbook of Exoplanets, eds. Hans
J. Deeg and Juan Antonio Belmonte (Springer-Verlag
Enhancement of lipase activity in non-aqueous media upon immobilization on multi-walled carbon nanotubes
<p>Abstract</p> <p>Background</p> <p>Immobilization of biologically active proteins on nanosized surfaces is a key process in bionanofabrication. Carbon nanotubes with their high surface areas, as well as useful electronic, thermal and mechanical properties, constitute important building blocks in the fabrication of novel functional materials.</p> <p>Results</p> <p>Lipases from <it>Candida rugosa </it>(CRL) were found to be adsorbed on the multiwalled carbon nanotubes with very high retention of their biological activity (97%). The immobilized biocatalyst showed 2.2- and 14-fold increases in the initial rates of transesterification activity in nearly anhydrous hexane and water immiscible ionic liquid [Bmim] [PF6] respectively, as compared to the lyophilized powdered enzyme. It is presumed that the interaction with the hydrophobic surface of the nanotubes resulted in conformational changes leading to the 'open lid' structure of CRL. The immobilized enzyme was found to give 64% conversion over 24 h (as opposed to 14% with free enzyme) in the formation of butylbutyrate in nearly anhydrous hexane. Similarly, with ionic liquid [Bmim] [PF6], the immobilized enzyme allowed 71% conversion as compared to 16% with the free enzyme. The immobilized lipase also showed high enantioselectivity as determined by kinetic resolution of (±) 1-phenylethanol in [Bmim] [PF6]. While free CRL gave only 5% conversion after 36 h, the immobilized enzyme resulted in 37% conversion with > 99% enantiomeric excess. TEM studies on the immobilized biocatalyst showed that the enzyme is attached to the multiwalled nanotubes.</p> <p>Conclusion</p> <p>Successful immobilization of enzymes on nanosized carriers could pave the way for reduced reactor volumes required for biotransformations, as well as having a use in the construction of miniaturized biosensensor devices.</p
Search for CP violation in D+→ϕπ+ and D+s→K0Sπ+ decays
A search for CP violation in D + → ϕπ + decays is performed using data collected in 2011 by the LHCb experiment corresponding to an integrated luminosity of 1.0 fb−1 at a centre of mass energy of 7 TeV. The CP -violating asymmetry is measured to be (−0.04 ± 0.14 ± 0.14)% for candidates with K − K + mass within 20 MeV/c 2 of the ϕ meson mass. A search for a CP -violating asymmetry that varies across the ϕ mass region of the D + → K − K + π + Dalitz plot is also performed, and no evidence for CP violation is found. In addition, the CP asymmetry in the D+s→K0Sπ+ decay is measured to be (0.61 ± 0.83 ± 0.14)%
flavour tagging using charm decays at the LHCb experiment
An algorithm is described for tagging the flavour content at production of
neutral mesons in the LHCb experiment. The algorithm exploits the
correlation of the flavour of a meson with the charge of a reconstructed
secondary charm hadron from the decay of the other hadron produced in the
proton-proton collision. Charm hadron candidates are identified in a number of
fully or partially reconstructed Cabibbo-favoured decay modes. The algorithm is
calibrated on the self-tagged decay modes and using of data collected by the LHCb
experiment at centre-of-mass energies of and
. Its tagging power on these samples of
decays is .Comment: All figures and tables, along with any supplementary material and
additional information, are available at
http://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-027.htm
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