1,693 research outputs found
An Approach to Accuracy Improvements in the Flexible Machining of Curved Profiles
This article describes a clamping concept for the flexible machining of spatially curved profiles developed at the wbk Institute of Production Science of the Universität Karlsruhe (TH). Simple geometrical considerations form the basis of the prototypically implemented clamping system design. The approach presented in this article allows for accuracy improvements regarding the positioning of the profile in the clamping system on the basis of markings applied onto the surface of the profile. Besides, the preliminary test rig set up and first results on the detection of the markings by means of digital image processing are presented
Fundamental limitations for quantum and nano thermodynamics
The relationship between thermodynamics and statistical physics is valid in
the thermodynamic limit - when the number of particles becomes very large.
Here, we study thermodynamics in the opposite regime - at both the nano scale,
and when quantum effects become important. Applying results from quantum
information theory we construct a theory of thermodynamics in these limits. We
derive general criteria for thermodynamical state transformations, and as
special cases, find two free energies: one that quantifies the
deterministically extractable work from a small system in contact with a heat
bath, and the other that quantifies the reverse process. We find that there are
fundamental limitations on work extraction from nonequilibrium states, owing to
finite size effects and quantum coherences. This implies that thermodynamical
transitions are generically irreversible at this scale. As one application of
these methods, we analyse the efficiency of small heat engines and find that
they are irreversible during the adiabatic stages of the cycle.Comment: Final, published versio
Automatic medical encoding with SNOMED categories
BACKGROUND: In this paper, we describe the design and preliminary evaluation of a new type of tools to speed up the encoding of episodes of care using the SNOMED CT terminology. METHODS: The proposed system can be used either as a search tool to browse the terminology or as a categorization tool to support automatic annotation of textual contents with SNOMED concepts. The general strategy is similar for both tools and is based on the fusion of two complementary retrieval strategies with thesaural resources. The first classification module uses a traditional vector-space retrieval engine which has been fine-tuned for the task, while the second classifier is based on regular variations of the term list. For evaluating the system, we use a sample of MEDLINE. SNOMED CT categories have been restricted to Medical Subject Headings (MeSH) using the SNOMED-MeSH mapping provided by the UMLS (version 2006). RESULTS: Consistent with previous investigations applied on biomedical terminologies, our results show that performances of the hybrid system are significantly improved as compared to each single module. For top returned concepts, a precision at high ranks (P0) of more than 80% is observed. In addition, a manual and qualitative evaluation on a dozen of MEDLINE abstracts suggests that SNOMED CT could represent an improvement compared to existing medical terminologies such as MeSH. CONCLUSION: Although the precision of the SNOMED categorizer seems sufficient to help professional encoders, it is concluded that clinical benchmarks as well as usability studies are needed to assess the impact of our SNOMED encoding method in real settings. AVAILABILITIES : The system is available for research purposes on: http://eagl.unige.ch/SNOCat
Differential Ganciclovir-Mediated Cytotoxicity and Bystander Killing in Human Colon Carcinoma Cell Lines Expressing Herpes Simplex Virus Thymidine Kinase
Overview summary The transfer of HSV-TK into tumor cells and the subsequent sensitization to GCV have resulted in successful antitumor effects both in vitro and in vivo for a variety of cancers. This study focuses on evaluating and comparing two colon carcinoma cell lines for their ability to metabolize GCV and transfer phosphorylated metabolites to neighboring non-HSV-TK-expressing cells (bystander effect). Here we demonstrate differences in HSV-TK expression, GCV triphosphate accumulation, and incorporation into DNA and their effect on cytotoxicity. We also provide evidence of the transfer of phosphorylated GCV to bystander cells in a cell line deficient in gap junctional intercellular communication.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63405/1/hum.1998.9.6-801.pd
VPP--DESIGN CRITERIA FOR AN INSTALLATION TO REMOVE HYDROGEN FLUORIDE AND FLUORINE FROM THE CELLS 1 AND 2 VENTILATION GASES PRIOR TO FILTRATION
Criteria are presented for a horizontal cocurrent spray nozzle scrubbing system designed to remove fluorine and hydrogen fluoride from the 3000 cfm of ventilation air passing through the Volatility Pilot Plant. A reduction of fluorine concentration from 1520 to <2 ppm during a total release of 68 lbs, and a reduction of hydrogen fluoride concentration from 4090 to <1 ppm during a total release of 200 lbs, will adequately protect the Fiberglas media filters. Six scrubbing states each containing four nozzle-throat spray units are needed with a 5 to 10% aqueous caustic potash recycle system pumping at a maximum rate of approximately 180 gal/min, with a range per nozzle from 3 to 7 gal/min. The scrubber will be 4 ft x 4 ft x approximately 25 ft, containing a deentrainment section of baffles and demister. The associated ventilation system hardware, services, and instrumentation requirements are given. (auth
Is This a Joke? Detecting Humor in Spanish Tweets
While humor has been historically studied from a psychological, cognitive and
linguistic standpoint, its study from a computational perspective is an area
yet to be explored in Computational Linguistics. There exist some previous
works, but a characterization of humor that allows its automatic recognition
and generation is far from being specified. In this work we build a
crowdsourced corpus of labeled tweets, annotated according to its humor value,
letting the annotators subjectively decide which are humorous. A humor
classifier for Spanish tweets is assembled based on supervised learning,
reaching a precision of 84% and a recall of 69%.Comment: Preprint version, without referra
Study of molecular spin-crossover complex Fe(phen)2(NCS)2 thin films
We report on the growth by evaporation under high vacuum of high-quality thin
films of Fe(phen)2(NCS)2 (phen=1,10-phenanthroline) that maintain the expected
electronic structure down to a thickness of 10 nm and that exhibit a
temperature-driven spin transition. We have investigated the current-voltage
characteristics of a device based on such films. From the space charge-limited
current regime, we deduce a mobility of 6.5x10-6 cm2/V?s that is similar to the
low-range mobility measured on the widely studied
tris(8-hydroxyquinoline)aluminium organic semiconductor. This work paves the
way for multifunctional molecular devices based on spin-crossover complexes
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