419 research outputs found
Crowdsourcing Dialect Characterization through Twitter
We perform a large-scale analysis of language diatopic variation using
geotagged microblogging datasets. By collecting all Twitter messages written in
Spanish over more than two years, we build a corpus from which a carefully
selected list of concepts allows us to characterize Spanish varieties on a
global scale. A cluster analysis proves the existence of well defined
macroregions sharing common lexical properties. Remarkably enough, we find that
Spanish language is split into two superdialects, namely, an urban speech used
across major American and Spanish citites and a diverse form that encompasses
rural areas and small towns. The latter can be further clustered into smaller
varieties with a stronger regional character.Comment: 10 pages, 5 figure
Interactive exploration of population scale pharmacoepidemiology datasets
Population-scale drug prescription data linked with adverse drug reaction
(ADR) data supports the fitting of models large enough to detect drug use and
ADR patterns that are not detectable using traditional methods on smaller
datasets. However, detecting ADR patterns in large datasets requires tools for
scalable data processing, machine learning for data analysis, and interactive
visualization. To our knowledge no existing pharmacoepidemiology tool supports
all three requirements. We have therefore created a tool for interactive
exploration of patterns in prescription datasets with millions of samples. We
use Spark to preprocess the data for machine learning and for analyses using
SQL queries. We have implemented models in Keras and the scikit-learn
framework. The model results are visualized and interpreted using live Python
coding in Jupyter. We apply our tool to explore a 384 million prescription data
set from the Norwegian Prescription Database combined with a 62 million
prescriptions for elders that were hospitalized. We preprocess the data in two
minutes, train models in seconds, and plot the results in milliseconds. Our
results show the power of combining computational power, short computation
times, and ease of use for analysis of population scale pharmacoepidemiology
datasets. The code is open source and available at:
https://github.com/uit-hdl/norpd_prescription_analyse
Fabrication of optical planar waveguides in by He-ion implantation
In this paper, planar waveguides produced by He-ion implantation have been demonstrated in undoped and Yb-doped KY(WO/sub 4/)/sub 2/ crystals. The effective refractive indices of guided modes in surface planar waveguides were measured by dark m-line spectroscopy and the refractive index profiles were reconstructed by calculations based on the inverse WKB method. The end-faces of implanted crystals were polished and the waveguiding properties of the obtained planar structures were investigated using a laser diode at 980 nm and a CCD camera
Wirksamkeit, Zweckmäßigkeit und Wirtschaftlichkeit des multimodalen Behandlungsansatzes bei chronisch lumbalen Rückenschmerzen
Zusammenfassung: Hintergrund: Der Nachweis der Behandlungskriterien Wirksamkeit, Zweckmäßigkeit und Wirtschaftlichkeit ist bei chronisch lumbalen Rückenschmerzen ["chronic low back pain" (CLBP)] notwendig, da Kostenträger die Übernahme von Behandlungskosten hiervon abhängig machen. Material und Methoden: Eine systematische Literatursuche zu den Behandlungskriterien der interdisziplinären, multimodalen Schmerztherapie ["multidisciplinary treatment" (MDT)] bietet einen Überblick über die aktuelle Literatur zur Behandlung von CLBP. Ergebnisse: Auf die moderate Wirksamkeit von MDT weisen 8Übersichtsarbeiten hin, wenn auch mit einigen Einschränkungen. Die Ergebnisse von 6 bisher in keine Übersichtsarbeit eingeschlossenen Originalarbeiten stützen die Ergebnisse der Übersichtsarbeiten. Die Langzeitergebnisse von MDT und operativen Behandlungen sind, bei höheren Kosten und Risiken für operative Behandlungen, vergleichbar. Die Wirtschaftlichkeit von MDT erreicht in 3Originalarbeiten eine moderate bis hohe Evidenz. Schlussfolgerungen: MDT sind sowohl moderat wirksam als auch wirtschaftlich. Daher sind sie eine kostengünstigere Behandlungsalternative zu operativen Verfahre
Crowdbreaks: Tracking Health Trends Using Public Social Media Data and Crowdsourcing
In the past decade, tracking health trends using social media data has shown great promise, due to a powerful combination of massive adoption of social media around the world, and increasingly potent hardware and software that enables us to work with these new big data streams. At the same time, many challenging problems have been identified. First, there is often a mismatch between how rapidly online data can change, and how rapidly algorithms are updated, which means that there is limited reusability for algorithms trained on past data as their performance decreases over time. Second, much of the work is focusing on specific issues during a specific past period in time, even though public health institutions would need flexible tools to assess multiple evolving situations in real time. Third, most tools providing such capabilities are proprietary systems with little algorithmic or data transparency, and thus little buy-in from the global public health and research community. Here, we introduce Crowdbreaks, an open platform which allows tracking of health trends by making use of continuous crowdsourced labeling of public social media content. The system is built in a way which automatizes the typical workflow from data collection, filtering, labeling and training of machine learning classifiers and therefore can greatly accelerate the research process in the public health domain. This work describes the technical aspects of the platform, thereby covering the functionalities at its current state and exploring its future use cases and extensions
Ultrahigh resolution optical coherence tomography using a superluminescent light source
A superluminescent Ti:Al2O3 crystal is demonstrated as a light source for ultrahigh resolution optical coherence tomography (OCT). Single spatial mode, fiber coupled output powers of ~40 μW can be generated with 138 nm bandwidth using a 5 W frequency doubled, diode pumped laser, pumping a thin Ti:Al2O3 crystal. Ultrahigh resolution OCT imaging is demonstrated with 2.2 μm axial resolution in air, or 1.7 μm in tissue, with >86 dB sensitivity. This light source provides a simple and robust alternative to femtosecond lasers for ultrahigh resolution OCT imaging
Keep calm and carry on vaccinating: Is anti-vaccination sentiment contributing to declining vaccine coverage in England?
BACKGROUND: In England, coverage for childhood vaccines have decreased since 2012/13 in the context of an increasingly visible anti-vaccination discourse. We determined whether anti-vaccination sentiment is the likely cause of this decline in coverage. METHODS: Descriptive study triangulating a range of data sources (vaccine coverage, cross-sectional survey of attitudes towards vaccination, UK-specific Twitter social media) and assessing them against the following Bradford Hill criteria: strength of association, consistency, specificity, temporality, biological gradient and coherence. RESULTS: Strength of association: compared with well-documented vaccine scares, the decline in childhood vaccination seen since 2012/13 is 4-20 times smaller; consistency: while coverage for completed courses of the hexavalent and meningococcal vaccines decreased by 0.5-1.2 percentage points (pp) between 2017 and 2019, coverage for the first dose of these vaccines increased 0.5-0.7 pp; specificity: Since 2012-13, coverage decreased for some vaccines (hexavalent, MMR, HPV, shingles) and increased for others (MenACWY, Td/IPV, antenatal pertussis, influenza in 2 years of children), with no age-specific patterns. Temporality and biological gradient: the decline in vaccine coverage was preceded by an increase in vaccine confidence and a decrease in the proportion of parents encountering anti-vaccination materials. Coherence: attitudes towards vaccination expressed on Twitter in the UK became increasingly positive between 2017 and 2019 as vaccine coverage for childhood vaccines decreased. CONCLUSIONS: In England, trends in vaccine coverage between 2012/13 and 2018/19 were not homogenous and varied in magnitude and direction according to vaccine, dose and region. In addition, confidence in vaccines increased during the same period. These findings are not compatible with anti-vaccination sentiment causing a decline in vaccine coverage In England
Digital quantum simulation of spin models with circuit quantum electrodynamics
Systems of interacting quantum spins show a rich spectrum of quantum phases
and display interesting many-body dynamics. Computing characteristics of even
small systems on conventional computers poses significant challenges. A quantum
simulator has the potential to outperform standard computers in calculating the
evolution of complex quantum systems. Here, we perform a digital quantum
simulation of the paradigmatic Heisenberg and Ising interacting spin models
using a two transmon-qubit circuit quantum electrodynamics setup. We make use
of the exchange interaction naturally present in the simulator to construct a
digital decomposition of the model-specific evolution and extract its full
dynamics. This approach is universal and efficient, employing only resources
which are polynomial in the number of spins and indicates a path towards the
controlled simulation of general spin dynamics in superconducting qubit
platforms.Comment: 12 pages, 9 figure
Fabrication of optical planar and channel waveguides in Yb<sup>3+</sup> doped KY(WO<sub>4</sub>)<sub>2</sub> by He-ion implantation
Light ion implantation can be regarded as a universal tool for fabricating low-loss waveguide structures in optically active oxide materials. We have fabricated planar optical waveguides in :(2%) crystals by implanting He+ ions at 1.5 MeV, with doses ranging from 1 to 3x10^16 ions/cm2. An optical barrier with a decreased effective refractive index was created at the end of the ions' tracks, situated approximately 3.5 μm below the surface. The change in refractive index with respect to the bulk value and its stability to thermal treatment were investigated by dark m-line spectroscopy. Surface channel waveguides were obtained by writing sidewalls into the planar guiding layer by implantation through a slit. The sidewalls were produced by keeping the ion energy fixed and varying the incident angle of implantation. Channel waveguides of 5-μm width and 4-μm depth were obtained in the regions between the implanted sidewalls. Beam-propagation parameters were measured by investigating the output profile of end-coupled, fundamental-mode laser light at 980 nm. The results of loss measurements will be presented at the conference
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