2,605 research outputs found
Simulating quantum effects of cosmological expansion using a static ion trap
We propose a new experimental testbed that uses ions in the collective ground
state of a static trap for studying the analog of quantum-field effects in
cosmological spacetimes, including the Gibbons-Hawking effect for a single
detector in de Sitter spacetime, as well as the possibility of modeling
inflationary structure formation and the entanglement signature of de Sitter
spacetime. To date, proposals for using trapped ions in analog gravity
experiments have simulated the effect of gravity on the field modes by directly
manipulating the ions' motion. In contrast, by associating laboratory time with
conformal time in the simulated universe, we can encode the full effect of
curvature in the modulation of the laser used to couple the ions' vibrational
motion and electronic states. This model simplifies the experimental
requirements for modeling the analog of an expanding universe using trapped
ions and enlarges the validity of the ion-trap analogy to a wide range of
interesting cases.Comment: (v2) revisions based on referee comments, figure added for clarity;
(v1) 17 pages, no figure
Visits of Sovereignty and the articulation of the national and the local in France and Germany on the eve of World War I
This paper seeks to explore the problems and potentialities of asymmetrical historical comparison by examining visits by heads of State to the provinces in Germany and France on the eve of WW I. This act of political legitimisation and representation is analysed through the lens of the practical organization of the event understood as an administrative routine, thereby bringing into question many of the categories routinely mobilised to describe and to oppose two models of national integration
Linked data and online classifications to organise mined patterns in patient data
In this paper, we investigate the use of web data resources in medicine, especially through medical classifications made available using the principles of Linked Data, to support the interpretation of patterns mined from patient care trajectories. Interpreting such patterns is naturally a challenge for an analyst, as it requires going through large amounts of results and access to sufficient background knowledge. We employ linked data, especially as exposed through the BioPortal system, to create a navigation structure within the patterns obtained form sequential pattern mining. We show how this approach provides a flexible way to explore data about trajectories of diagnoses and treatments according to different medical classifications
On mining complex sequential data by means of FCA and pattern structures
Nowadays data sets are available in very complex and heterogeneous ways.
Mining of such data collections is essential to support many real-world
applications ranging from healthcare to marketing. In this work, we focus on
the analysis of "complex" sequential data by means of interesting sequential
patterns. We approach the problem using the elegant mathematical framework of
Formal Concept Analysis (FCA) and its extension based on "pattern structures".
Pattern structures are used for mining complex data (such as sequences or
graphs) and are based on a subsumption operation, which in our case is defined
with respect to the partial order on sequences. We show how pattern structures
along with projections (i.e., a data reduction of sequential structures), are
able to enumerate more meaningful patterns and increase the computing
efficiency of the approach. Finally, we show the applicability of the presented
method for discovering and analyzing interesting patient patterns from a French
healthcare data set on cancer. The quantitative and qualitative results (with
annotations and analysis from a physician) are reported in this use case which
is the main motivation for this work.
Keywords: data mining; formal concept analysis; pattern structures;
projections; sequences; sequential data.Comment: An accepted publication in International Journal of General Systems.
The paper is created in the wake of the conference on Concept Lattice and
their Applications (CLA'2013). 27 pages, 9 figures, 3 table
The contribution of drug import to the cost of tuberculosis treatment: A cost analysis of longer, shorter, and short drug regimens for Karakalpakstan, Uzbekistan
Tuberculosis (TB) programs depend on a continuous supply of large amounts of high-quality TB drugs. When TB programs procure TB drugs from international suppliers, such as the Global Drug Facility, they can incur import costs for international transport, customs clearance, and national transport. We assessed the drug costs and import costs of 18 longer (≥18 months), 10 shorter (9-12 months), and 8 short (≤6 months) drug regimens for drug-sensitive (DS) and multidrug-resistant (MDR)-TB treatment. Costs per regimen were estimated by multiplying recommended drug amounts with 2021 Global Drug Facility prices and drug import costs of a TB program in Karakalpakstan, Uzbekistan. The standard short-course treatment of DS-TB requires taking 730 fixed-dose combination tablets, which weigh 0.79 kg and cause an import cost of 43). A new 4-month DS-TB regimen requires taking 1358 tablets, which weigh 1.1 kg and cause an import cost of 233). MDR-TB regimens that last between 24 weeks and 20 months involve 546-9368 tablets and injections. The drugs for these MDR-TB regimens were estimated to weigh 0.42-96 kg and cause an import cost of 360-15,028). In a multivariable regression analysis, an additional treatment month increased the import cost of a drug regimen by 133 (95% CI: 47 to 219). The variable and potentially sizable import costs of TB regimens can affect the financial needs of TB programs. Drug regimens that are shorter and all-oral tend to reduce import costs compared to longer regimens and regimens including an injectable drug
Experimental and Numerical Investigation of Dispersed and Continuous Liquid Film under Boiling conditions
[EN] In this work, both experimental and numerical investigations have been carried out in order to improve the
modelling of the vaporization of wall liquid-deposits in internal combustion engines. A comprehensive model is
suggested for the vaporization of liquid films in the different boiling regimes, including nucleate boiling regime, the
Leidenfrost boiling regime, as well as the transition boiling regime occurring between the two latter. This work
extends the validity of the Liquid Film Boiling model (Habchi, Oil & Gas Science and Technology – Rev. IFP, Vol.
65, No. 2, 2010) for dispersed liquid films that may be formed when a dilute spray impinges a wall. A sub-grid
liquid film is indeed considered when the wetted-area is smaller than the wall cell-face area. A sessile droplet
model is used to estimate the wall area wetted by the liquid film and whether it is resolved by the grid or located in
the sub-grid scale (SGS). In addition, a novel Leidenfrost vaporization model is proposed for spray droplets
located near a hot wall. The above vaporisation/boiling models has been implemented in the Large-Eddy
simulation (LES) AVBP code. The validation has been carried out using two different experiments. First, the
experimental lifetime curve of a sessile droplet (Stanglmaier et al., SAE paper 2002-01-0838) has been used for a
quantitative validation in the different boiling regimes. Second, the wall impingement of a heptane spray from a
typical gasoline injector from Continental Automotive, has been simulated. The numerical results obtained under
boiling conditions, are compared to the liquid film footprints and lifetime provided by the Refractive Index Matching
(RIM) experiment which is described in this article.Habchi, C.; Lamarque, N.; Helie, J.; Jay, S. (2017). Experimental and Numerical Investigation of Dispersed and Continuous Liquid Film under Boiling conditions. En Ilass Europe. 28th european conference on Liquid Atomization and Spray Systems. Editorial Universitat Politècnica de València. 921-928. https://doi.org/10.4995/ILASS2017.2017.4632OCS92192
Programme costs of longer and shorter tuberculosis drug regimens and drug import: a modelling study for Karakalpakstan, Uzbekistan
Background: The introduction of new and often shorter tuberculosis (TB) drug regimens affects the cost of TB programmes.
Methods: We modelled drug purchase and import costs for 20-month, 9-month and 4- to 6-month TB drug regimens based on 2016–2020 treatment numbers from a TB programme in Karakalpakstan, Uzbekistan, and 2021 Global Drug Facility prices.
Results: On average, 2225±374 (±sd) people per year started TB treatment, 30±2.1% of whom were diagnosed with drug-resistant forms of TB. Transitioning from a 6-month to a 4-month drug-susceptible (DS)-TB drug regimen increased the TB programme's annual DS-TB drug cost from USD 65±10 K to USD 357±56 K (p<0.001) and its drug import cost from USD 6.4±1.0 K to USD 9.3±1.4 K (p=0.008). Transitioning from a 20-month all-oral multidrug-resistant (MDR)-TB drug regimen to a 9-month MDR-TB drug regimen with an injectable antibiotic decreased the TB programme's annual MDR-TB drug cost from USD 1336±265 K to USD 266±53 K (p<0.001) and had no significant effect on the drug import cost (USD 28±5.5 K versus USD 27±5.4 K; p=0.88). Purchasing (USD 577±114 K) and importing (USD 3.0±0.59 K) the 6-month all-oral MDR-TB drug regimen cost more than procuring the 9-month MDR-TB drug regimen but less than the 20-month all-oral MDR-TB drug regimen (both p<0.01).
Conclusion: Introducing new and shorter TB drug regimens could increase the cost of TB programmes with low drug resistance rates and decrease the cost of TB programmes with high drug resistance rates
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