1,448 research outputs found
Velocitap: Investigating fast mobile text entry using sentence-based decoding of touchscreen keyboard input
We present VelociTap: a state-of-the-art touchscreen keyboard
decoder that supports a sentence-based text entry approach.
VelociTap enables users to seamlessly choose from
three word-delimiter actions: pushing a space key, swiping
to the right, or simply omitting the space key and letting the
decoder infer spaces automatically. We demonstrate that VelociTap
has a significantly lower error rate than Google’s keyboard
while retaining the same entry rate. We show that intermediate
visual feedback does not significantly affect entry
or error rates and we find that using the space key results
in the most accurate results. We also demonstrate that enabling
flexible word-delimiter options does not incur an error
rate penalty. Finally, we investigate how small we can make
the keyboard when using VelociTap. We show that novice
users can reach a mean entry rate of 41 wpm on a 40mm wide
smartwatch-sized keyboard at a 3% character error rate
High field magnetic resonant properties of beta'-(ET)2SF5CF2SO3
A systematic electron spin resonance (ESR) investigation of the low
temperature regime for the (ET)2SF5CF2SO3 system was performed in the frequency
range of ~200-700 GHz, using backward wave oscillator sources, and at fields up
to 25 T. Newly acquired access to the high frequency and fields shows
experimental ESR results in agreement with the nuclear magnetic resonance (NMR)
investigation, revealing evidence that the transition seen at 20 K is not of
conventional spin-Peierls order. A significant change of the spin resonance
spectrum in beta'-(ET)2SF5CF2SO3 at low temperatures, indicates a transition
into a three-dimensional-antiferromagnetic (3D AFM) phase.Comment: 4 pages, 7 figures, minor grammatical change
Charge Ordering in alpha-(BEDT-TTF)2I3 by synchrotron x-ray diffraction
The spatial charge arrangement of a typical quasi-two-dimensional organic
conductor alpha-(BEDT-TTF)2I3 is revealed by single crystal structure analysis
using synchrotron radiation. The results show that the horizontal stripe type
structure, which was suggested by mean field theory, is established. We also
find the charge disproportion above the metal-insulator transition temperature
and a significant change in transfer integrals caused by the phase transition.
Our result elucidates the insulating phase of this material as a 2k_F charge
density localization.Comment: 8 pages, 5 figures, 1 tabl
Resilience of bacterial quorum sensing against fluid flow
Quorum sensing (QS) is a population-density dependent chemical process that enables bacteria to communicate based on the production, secretion and sensing of small inducer molecules. While recombinant constructs have been widely used to decipher the molecular details of QS, how those findings translate to natural QS systems has remained an open question. Here, we compare the activation of natural and synthetic Pseudomonas aeruginosa LasI/R QS systems in bacteria exposed to quiescent conditions and controlled flows. Quantification of QS-dependent GFP expression in suspended cultures and in surface-attached microcolonies revealed that QS onset in both systems was similar under quiescent conditions but markedly differed under flow. Moderate flow (Pe > 25) was sufficient to suppress LasI/R QS recombinantly expressed in Escherichia coli, whereas only high flow (Pe > 102) suppressed QS in wild-type P. aeruginosa. We suggest that this difference stems from the differential production of extracellular matrix and that the matrix confers resilience against moderate flow to QS in wild-type organisms. These results suggest that the expression of a biofilm matrix extends the environmental conditions under which QS-based cell-cell communication is effective and that findings from synthetic QS circuits cannot be directly translated to natural systems
Structural and Mechanistic Insights into Fast Lithium-Ion Conduction in Li4SiO4-Li3PO4 Solid Electrolytes.
Solid electrolytes that are chemically stable and have a high ionic conductivity would dramatically enhance the safety and operating lifespan of rechargeable lithium batteries. Here, we apply a multi-technique approach to the Li-ion conducting system (1-z)Li4SiO4-(z)Li3PO4 with the aim of developing a solid electrolyte with enhanced ionic conductivity. Previously unidentified superstructure and immiscibility features in high-purity samples are characterized by X-ray and neutron diffraction across a range of compositions (z = 0.0-1.0). Ionic conductivities from AC impedance measurements and large-scale molecular dynamics (MD) simulations are in good agreement, showing very low values in the parent phases (Li4SiO4 and Li3PO4) but orders of magnitude higher conductivities (10(-3) S/cm at 573 K) in the mixed compositions. The MD simulations reveal new mechanistic insights into the mixed Si/P compositions in which Li-ion conduction occurs through 3D pathways and a cooperative interstitial mechanism; such correlated motion is a key factor in promoting high ionic conductivity. Solid-state (6)Li, (7)Li, and (31)P NMR experiments reveal enhanced local Li-ion dynamics and atomic disorder in the solid solutions, which are correlated to the ionic diffusivity. These unique insights will be valuable in developing strategies to optimize the ionic conductivity in this system and to identify next-generation solid electrolytes.The ALISTORE ERI and CNRS are acknowledged for supporting Y.D. through a joint Ph.D. scholarship between Picardie (France) and Bath (UK). The authors thank D. Sheptyakov (PSI, Switzerland) and M. Bianchini (ILL-Grenoble, France) for assistance with neutron diffraction experiments, and M. T. Dunstan (Cambridge, UK) for assistance with NMR experiments. Financial support from the EPSRC Energy Materials Programme (Grant EP/K016288) is gratefully acknowledged. The HPC Materials Chemistry Consortium (EP/L000202) allowed use of the ARCHER facilities. O.P. and S.E. acknowledge support from a Marie Skłodowska-Curie Fellowship (H2020-MSCA-IF-2014-EF, no. 655444) and an ERASMUS+ scholarship, respectively.This is the author accepted manuscript. The final version is available from the American Chemical Society via http://dx.doi.org/10.1021/jacs.5b0444
N-Methylimidazole Promotes The Reaction Of Homophthalic Anhydride With Imines
The addition of N-methylimidazole (NMI) to the reaction of homophthalic anhydride with imines such as pyridine-3-carboxaldehyde-N-trifluoroethylimine (9) reduces the amount of elimination byproduct and improves the yield of the formal cycloadduct, tetrahydroisoquinolonic carboxylate 10. Carboxanilides of such compounds are of interest as potential antimalarial agents. A mechanism that rationalizes the role of NMI is proposed, and a gram-scale procedure for the synthesis and resolution of 10 is also described
Chronic Hepatitis B Virus Coinfection Is Associated With Renal Impairment Among Zambian HIV-Infected Adults
Among 6789 HIV-infected Zambian adults screened for hepatitis B virus (HBV) coinfection, estimated glomerular filtration rate (eGFR) was 50-90 mL/minute/1.73 m2 in 17.6% and <50 mL/minute/1.73 m2 in 2.5%. Human immunodeficiency virus/HBV coinfection was associated with eGFR <50 mL/minute/1.73 m2 (adjusted odds ratio, 1.96 [95% confidence interval, 1.34-2.86]), adjusted for age, sex, CD4+ count, and World Health Organization disease stag
Implantable loop recorder monitoring for refining management of children with inherited arrhythmia syndromes
BACKGROUND: Implantable loop recorders (ILRs) are conventionally utilized to elucidate the mechanism of atypical syncope. The objective of this study was to assess the impact of these devices on management of pediatric patients with known or suspected inherited arrhythmia syndromes. METHODS AND RESULTS: A retrospective chart review was undertaken of all pediatric patients with known or suspected inherited arrhythmia syndromes in whom an ILR was implanted from 2008 to 2015. Captured data included categorization of diagnosis, treatment, transmitted tracings, and the impact of ILR tracings on management. Transmissions were categorized as symptomatic, autotriggered, or routine. Actionable transmissions were abnormal tracings that directly resulted in a change of medical or device therapy. A total of 20 patients met the stated inclusion criteria (long QT syndrome, n=8, catecholaminergic polymorphic ventricular tachycardia,n=9, Brugada syndrome, n=1, arrhythmogenic right ventricular cardiomyopathy, n=2), with 60% of patients being genotype positive. Primary indication for implantation of ILR included ongoing monitoring +/− symptoms (n=15, 75%), suspicion of noncompliance (n=1, 5%), and liberalization of recommended activity restrictions (n=4, 25%). A total of 172 transmissions were received in patients with inherited arrhythmia syndromes, with 7% yielding actionable data. The majority (52%) of symptom events were documented in the long QT syndrome population, with only 1 tracing (5%) yielding actionable data. Automatic transmissions were mostly seen in the catecholaminergic polymorphic ventricular tachycardia cohort (81%), with 21% yielding actionable data. There was no actionable data in routine transmissions. CONCLUSIONS: ILRs in patients with suspected or confirmed inherited arrhythmia syndromes may be useful for guiding management. Findings escalated therapies in 30% of subjects. As importantly, in this high‐risk population, the majority of symptom events represented normal or benign rhythms, reassuring patients and physicians that no further intervention was required
Activation and Oxidation of Mesitylene C−H Bonds by (Phebox)Iridium(III) Complexes
A pincer iridium(III) complex, (Phebox)Ir(OAc)_2OH_2 (1) (Phebox = 3,5-dimethylphenyl-2,6-bis(oxazolinyl)), selectively cleaves the benzylic C–H bond of mesitylene to form an isolable iridium mesityl complex, (Phebox)Ir(mesityl)(OAc) (3), in >90% yield. The trifluoroacetate analogue, (Phebox)Ir(OCOCF_3)_2OH_2 (2), was synthesized to compare with complex 1 for C–H activation, and (Phebox)Ir(mesityl)(OCOCF_3) (4) was synthesized by ligand exchange of complex 3. Both complexes 1 and 2 catalyze H/D exchange between mesitylene and D2O at 180 °C, exclusively at the benzylic position; 2 gave a higher turnover number (11 TO) than 1 (6 TO) in 12 h. Using d4-acetic acid as the source of deuterium, up to 92 turnovers of benzylic H/D exchange of mesitylene were obtained with complex 1. (Phebox)Ir(OCOCF3)_2OH_2 catalyzed the benzylic C–H oxidation of mesitylene using Ag_2O as a terminal oxidant at 130 °C, to form 3,5-dimethylbenzaldehyde and 3,5-dimethylbenzoic acid in 35% ± 4% yield (5.1 ± 0.6 TO). DFT calculations were used to investigate two possible pathways for the catalytic oxidation of mesitylene: (1) C–H activation followed by oxy-functionalization and (2) Ir-oxo formation followed by outer-sphere C–H hydroxylation. Results of calculations of the C–H activation pathway appear to be the more consistent with the experimental observations
Master of Social Work Portfolio
https://scholarworks.umt.edu/grad_portfolios/1408/thumbnail.jp
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